Mac OSX Lion Secure Backup to Time Capsule with size limit

Update: On August 31 I updated this post with a more detailed description that should always work

I was among the 1M people who downloaded the newest version of Mac OSX operating system 10.7 “Lion” in the first 24 hours but to make sure my productivity doesn’t suffer I initially installed it on my wife’s personal Mac. She doesn’t use it so much these days anyway. After some trying out I finally installed Lion on my Mac this past weekend. With two Macs on Lion I found a cool way of keeping all our backups on a single Time Capsule drive. Here's how I did it.

Note: This is a technical post for Mac OSX Lion users. I wrote it because I didn’t find a single easy-to-digest how-to for configuring secure Time Machine backups on Lion. Sorry for this technical stuff, I just hope it's useful for some :-
My setup: 2 Macbook Airs and one Time Capsule

So we have 2 Macbook Airs at home – one belongs to my wife and one to me. We want to be able to:

1) Backup both Airs wirelessly to the same Time Capsule
2) Make sure we have enough space on the Time Capsule drive for our backups and also some other media files
3) Make the backups encrypted for maximum safety

New Lion’s Time Machine is good and secure... but needs tweaking.

The new Time Machine in Lion can encrypt your backup drive, but only if it’s connected via USB. If it’s a Time Capsule, no dice. Second thing, the Time Machine backs up until the disk is full. If we have two Macs we want to make sure we have space for each other’s backups and we have room for some media files. For that we need to create “virtual, encrypted backup hard disks called sparse bundles” on the Time Capsule for each of our Macs. Here’s what I did:

Step 1. Enable FileVault2 on the Mac

I was using FileVault on the Mac so after I upgraded to Lion, I went to “System Preferences” and had to first disable what Apple now calls “Legacy FileVault” and decrypt my user account. It takes a few minutes, once done I went ahead and enabled the new FileVault on the entire hard disk. Again, took some time to complete. Now my entire disk on the Mac is encrypted.

Step 2. Prepare Encrypted backup disk (a.k.a. “Sparsebundle”)

I found this hint here - now let me upgrade it to the Lion. Just do the following:

1. Figure out the name of your computer (and make sure it doesn’t contain spaces).

This is important. Go to “Sharing” in “System Preferences” and rename your computer (mine is called “Jane”, don’t ask…)
Also find out the address of your main ethernet card (in the case of my Macbook Air it's the address of my wireless card) - go to "System Preferences", "Network" and click on your wireless card and go to "Advanced" and at the bottom of the page you'll see your "Wi-fi address"… or just type in the Terminal:

ifconfig en0 | grep ether

The result for me was: 04:0c:ce:dc:a6:78

Keep this address for later.

2. Open disk utility and create a new volume image on your Time Capsule drive like this:
a) Save As: ComputerName_EthernetAddress (without ":")

In my case: Jane_040ccedca678

(Computer name: Jane, Ethernet address without ":" is: 040ccedca678 - make sure to find out yours in the previous step)

b) Name: ComputerName (in my case: Jane)

c) Custom size, I chose 300 GB for now.

d) Format leave as it is, meaning: Mac OSX Extended (Journaled)

e) Encryption: choose 128-bit - it's fast and it's really secure

f) Partitions leave as it is, meaning: Single Partition, Apple Partition Map

g) Choose "sparse bundle disk image" - important.

The cool thing is that the virtual disk will be small at the beginning and will only reach it's size after many backups. I don't store too much media on my Air, so 300GB should be good for now. Initial backup was just 115GB. Plenty of room for the incremental backups now.

Size of the Sparsebundle file/disk can be increased later with one terminal command if you need that :-)

This way on our 1TB Time Capsule we have 600GB for backups and 400GB for media files (home videos and stuff).

Disk Utility asked me for a password. I chose one and saved it in the keychain. After the format, the disk has been mounted. Worked great so I unmounted it.

3. Open “Keychain Access” application (you'll need to provide your admin password here) and move the password from your personal keychain (usually called "login") to the “system” keychain.
Step 3. Do the first backup and you're set.

When Time Machine asks you to point the drive to backup to, just point to your Time Capsule drive where the encrypted sparsebundle resides. And go with the first backup!

Do your first backup. It will take a while, do it before going to sleep. Now the Time Machine will back up to this "Sparsebundle" encrypted virtual hard disk every time and will not take over your entire Time Capsule disk. The Time Machine will rename your disk to just "ComputerName.sparsebundle" - don't worry about it. It will find it for backups later.

Optional Step - schedule backups manually.

If you’re like me and you don’t like Time Machine backing up every hour, you can do an optional step – download TimeMachineEditor application and schedule your backups. This is how I do it:
TimeMachineEditor will disable your official Time Machine backup scheduler as it triggers backups by itself. My backups are being run 3 times a day and I think it’s more than enough.

Congratulations. You have secure backups on your Time Capsule in Lion and you’re set to be even more productive on your Mac. Good luck!

my web app me I'm Michael Sliwinski and I'm an entrepreneur who's also the...
.. Founder of - a time and project management web application
.. Editor of Productive! Magazine - a global PDF publication on productivity
.. and a blogger as well as a producer of a weekly 2-minute Productive! show.

Posted on Monday, July 25, 2011 (apple)

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Jul 27, 2011 04:16
Saving the password of your backup in the keychain of the system you are in the process of backing up is convenient, but if/when the time comes to restore because your main computer is stolen or corrupt you should also REMEMBER IT or have it stored safely ELSEWHERE (tip: use or you end up empty handed.

Also, an even better backup routine also has two sets of backups (ideally one local backup, one remote).

Nevertheless, a very helpful article on how to set this is up.

Michael Sliwinski
Jul 27, 2011 10:49
Storing passwords securely in a different location is also important. But to have a good backup solution with Time machine is just basics, but many people forget about basics. Thanks for your comments, Brusle!
Jul 29, 2011 18:46
Nice tutorial, but for some reason it doesn't work for me even though I've followed it to the letter.
I'm trying to backup my Macbook to a new 4th gen Time Capsule and Time Machine just keeps creating and mounting a new disk image while ignoring my homemade encrypted one. I've tried both the Wi-Fi and ethernet MAC-addresses in the name to no avail. Even tried dropping the whole MAC-address altogether, but that doesn't work either, Time Machine just adds number one (1) the the name of sparse bundle it is creating and happily goes on backing up my files onto that volume.

I'm trying to create a 750GB volume to my home folder in Time Capsule. Time Machine creates sparse bundle named like: computername.sparsebundle, mounts that volume and starts backing up.

Any ideas what might be happening and what can I do to resolve this issue?

Michael Sliwinski
Jul 29, 2011 19:54
I had the same issue when I just put my computer name as the sparse bundle name. The backup would create a file "JaneEyre 1.sparsebundle". I'd stop backup, renamed the newly created file to "something.sparsebundle" just to be safe and renamed my encrypted file name to "JaneEyre_MACADDRESS.sparsebundle" and re-initiated the backup. Then the backup went OK and then I removed the "something" file and all my subsequent backups went just fine. Let me know if it works for you.
Jul 30, 2011 12:53
Thanks for the tip Michael, that helped and now my encrypted image is used by the Time Machine.
This has to be some kind of bug, don't you think? There can be no reason why Time Machine would not accept an encrypted sparse bundle at first but then after renaming its own creation and putting MAC-address to the end of the name for file you created it suddenly does.
Perhaps this could even be considered a some kind of security issue; malware is sitting on the system, detects a first time Time Machine activity and stops the process at the right point, creates its own encrypted image with pre-determined password and waits... until there is a need to use the backup and then starts to demand something (money most likely) to allow user to access those backups. Far fetched maybe, but still.

But anyway, thanks for the tip and help solving my issue - maybe you should include the problem and the solution as a footnote since I can hardly imagine this affects only the two of us.

Michael Sliwinski
Jul 31, 2011 23:10
Mac OSX Lion is a great OS but it's still quite buggy. Doesn't seem as polished as Snow Leo was when it came out. This backup problem happened on my computer but didn't happen on my wife's Air. Don't know why. Glad it worked for you Tomi!
Aug 7, 2011 09:33
In your article you mention that you can change the space of the sparsebundle with one terminal command... what is that command?
Michael Sliwinski
Aug 9, 2011 09:14
Sparse bundle files with Time Machine backups can be easily resized if you need to. For example, if you want to resize your file, just go to terminal and type:

hdiutil resize -size 500g MyFile.sparsebundle

and it will now be resized to max size of 500GB - of course it will not occupy so much space until you put so much stuff in it (so many backups for example). Hope it helps.

Aug 17, 2011 19:07
Time Machine in Lion is a much ore mature product respect to Snow Leopard even with the few bugs that are in the new LION OS. At Dolly Drive we add the ability of bringing and performing your Time Machine backups were ever you are
Michael Sliwinski
Aug 24, 2011 14:42
Merging my Time Machine backup with a cloud-based solution will be my next logical step. For now it's good I'm backed up well at home :-)
Aug 24, 2011 20:02
great. works perfect for me.
thanks :)
Aug 24, 2011 23:01
Hi Micheal. I keep getting the issue with time machine creating a new file instead of using the one i created. maybe i misunderstood your fix. what do you mean by "JaneEyre_MACADDRESS.sparsebundle"? i literally have to write the world MACADDRESS? i tried that and also replacing such world with the wifi card address. in both cases my mac create a new sparse bundle. what should i do?
Aug 24, 2011 23:42
MIchael, let me clarify better. i created a file called ManuelaMac_0026bb1a57ee.sparsebundle following the process described above. 0026bb1a57ee is the wifi/mac address. when time machine starts backing up however, it creates a new file called ManuelaMac.tmp.sparsebundle ; i changed the name of this file to something.sparsebundle and the original file into several alternatives:


However, in all these cases time machines keeps creating a new file

what am i doing wrong? thank

Aug 31, 2011 11:34
Hi, do you have any feedback for me? thanks
Michael Sliwinski
Aug 31, 2011 15:02
I updated the post on Lion and Time Capsule encrypted backup with some more details that I tested last night on two Macbook Airs. I think the problem was with the Format of the sparsebundle disk - it shouldn't be "case-sensitive" like I posted the first time. It should be just "journaled". Riccardo please refresh this blog post and follow the instructions again and let me know if it worked for you. This worked on both my and my wife's Airs without a hiccup. Best!
Sep 1, 2011 23:01
Hi MIchael thank you for the suggestion. Unfortunately it did not work. i created a new sparse bundle formatted as just "journaled". all other settings stayed the same as in your previous post. thus i created ManuelaMac_0026bb1a57ee.sparsebundle

however, when mac starts backing up... time machine keeps creating a second bundle called ManuelaMac.sparsebundle and the original remains on the time machine. so the second is not just a renaming but a completely new file (without the proper setting)

Michael Sliwinski
Sep 3, 2011 10:49
I'm really sorry it doesn't work for you. I recently clean-installed my Air and did a backup with these instructions and it worked. Then I did a backup with my wife's Air again after upgrading her Air to Lion and it worked, too.

Are you sure you put also just your computer name in (b)? If you did follow all of my instructions here and it doesn't work for you, I'm really sorry for that. Can't trouble-shoot it anymore as it worked in all of my cases. Did you try to delete the automatically created file and hit backup again? It also didn't help?

Anyone had the same issues?

I'm really sorry Riccardo, hard to say why it doesn't work for you....

Oct 7, 2011 06:17
Same happened to me. (same as Ricardo) Any idea?
Oct 7, 2011 07:33
IMPORTANT: Please use your Ethernet MAC address! It does not work with the WIFI MAC address... (for Ricardo)
Michael Sliwinski
Oct 7, 2011 19:44
The MAC address you have to use is the one of your FIRST ethernet device (I read that somewhere). For my Macbook Air it's Wifi but maybe for iMacs or Mac Minis it's LAN? I'll check it on Monday with my Mac mini and let you know, but maybe Tom is right! Thanks!
Oct 15, 2011 23:47
Works now since 10 days. Only thing I could tink of: Try every MAC address you have. WIFI and ethernet...
Michael Sliwinski
Oct 16, 2011 11:36
Checking all MAC addresses is a good call. Time Machine backups configured like this work on all of my Macs and I'm really happy about this setup. Glad it works for you, Tom!
Michal Huszcza
Oct 16, 2011 12:18
"...but to make sure my productivity doesn’t suffer I initially installed it on my wife’s personal Mac" I like it!;):)
Michael Sliwinski
Oct 16, 2011 12:50
My wife's Mac wasn't used heavily at that time so I tried it first there. Many people make the mistake of testing new things on their "production" machines and later can't get anything done... Thanks for your comment Michal!
Oct 18, 2011 17:26
Thanks for that great tutorial. It worked for me with a WD MyBookLive NAS. Unfortunately every Backup initialization is very slow >5min and Disk utility is not responding when time machine mounts the backup image. Have you seen similar behaviour?

Best regards

Michael Sliwinski
Oct 18, 2011 19:45
With this technique the first backups were pretty slow but later they went fast. Now every new TM backup takes about 5 minutes total. I use Time Capsule and Wifi connection, and it's really fast here. Let's hope it speeds up on your end, Daniel!
Oct 29, 2011 12:23
It works this way with LION - No Renaming or otherwise!

First, thanks for a great post. It is much easier and quicker using Disk Utility for the sparcebundle than the terminal.

I had the same problem: Either TM would just create a new sparcebundle on its own, with a _1 name, OR TM would just be trying to access the volume, stalled in some sort of loop.

What works without the renaming fix:
1. Create new Disk Image directly on the TC using Disk Utility.
2. Save As : Computername_MacAdresse(Lan).sparcebundle (field a in guide)
3. Name: 'Time Machine Backups' (field b in guide)


Michael Sliwinski
Oct 29, 2011 17:24
Great advice on renaming disk to Time Machine Backups to make sure my technique works. Thanks for posting this, Nruub!
Oct 30, 2011 13:05
There is another way which will work even if you've already done a full backup.....

1. Do your first backup (or second or third, as long as the sparsebundle file has not already increased to a size greater than the limit you are setting out to achieve.

2. Temporarily switch off time machine (so it doesn't try and backup while you're doing this.

3. A sparsebundle is really a folder which Finder pretends is file (a bit like the programs in your applications folder). The maximum size for a sparsebundle file is stored in an xml file named Info.plist which lives inside the .sparsebundle folder.

4. If your time capsule disk is mounted (double click on it in finder) you can very easily access this from the command line.
a. Open the terminal (In Applications==>Utilities
b. type in
sudo nano /Volumes/time-capsule/tim.sparsebundle/Info.plist
[ yours will have a different volume and sparsebundle name obviously ]

c. If you have a 1TB time capsule the file will look something like this

<?xml version="1.0" encoding="UTF-8"?>


d. change the final number (998057361408 in this example) to a smaller number
(409600032768 will make it limited to 400GB)

e. press control-o to save and then control-x to exit
f. copy this file to its bckup counterpart... type in:
sudo cp /Volumes/time-capsule/tim.sparsebundle/Info.plist /Volumes/time-capsule/tim.sparsebundle/Info.bckup
e. close the terminal.

5. Turn on time machine again and relax.

Michael Sliwinski
Oct 30, 2011 17:19
Great advice on manipulating the backup manually, although it's very "geeky" :-) Great to learn where all this info is stored, though. Thanks for your comment, Timbo_phillips! This makes this thread really great and useful for everyone. Thanks for contributing!
Nov 6, 2011 06:18
Thank you so much Michael,

It works !

Michael Sliwinski
Nov 9, 2011 11:47
I'm so happy this method of secure backing up works for all of you guys on Lion with Time Machine. It's great that this practical yet technical article helped so many of you guys. Have a great day Alexandre and all the other folks reading and sharing this. Peace! :-)
Nov 10, 2011 02:28
Thank you so much for the info. I never though about adding one more layer of security to time machine backups. I should have done it a long time ago cause I bet it can be used under Leopard and Snow Leopard too.
Michael Sliwinski
Nov 10, 2011 07:30
Yes, I was securing my Time Machine backups already in Snow Leopard and Leopard. Now on Lion it was the first thing I did, too. Glad the info worked for you, Vale!
Nov 26, 2011 18:06
I'm experiencing an issue related to permissions on the disk.
On a mac with multiple users the volume for the backup, once mounted, has only privileges for the user that has created the sparseboundle. This affects usage for other users on the same machine: their backup are done by the system, but they can't restore from them.
Nov 28, 2011 18:49
I've managed to kind of solve the disk permissions issue. I've had to modify permissions for the backup volume itself, adding r+x for the group. This way other users have access to backups via Time Machine. The problem is that the Volume once mounted via Time Machine can't be unmounted.
Alex Patsay
Nov 30, 2011 07:28
I can see a lot of complaints before August 31st update. I just want to share that I've used this solution in September and it worked like a charm, with no issues whatsoever. Just follow the instructions step by step and it should be alright. BTW, for readers of my blog I've created my own version of the instruction in Russian:
Michael Sliwinski
Nov 30, 2011 17:01
So happy this solution of securely backing up macs to time capsule works now for all the folks. That's great. Vale, thanks for solving the problem with permissions. Alex, thanks for putting it up on your blog and crediting me there - that's nice :-)

Hope we don't have to recover our data all that often, though :-)

Horacio Narvaez-Mena
Dec 4, 2011 02:37
Hey Michael,
this is a great tutorial and very helpful. I am trying to set it up but I am stucked on the step in which you move the password from your personal keychain to the “system” keychain. I don't get which one I should move coz I see more than one. Hope you have the answer ;) Thanks in advance...
Horacio Narvaez-Mena
Dec 4, 2011 02:45
Me again! I figured it out ;) It was the password I just created, just realized it ... :P
Thanks anyway for the great tutorial, since I got my TC I wanted to set up the size of the backups...
Michael Sliwinski
Dec 6, 2011 19:59
Glad this tutorial works for all of you guys. It is really useful to be able to set up the Time Machine backups well. Once set, they just work (like Apple stuff usually does) and they work well for me, too. Horacio, glad you made it work!
stuck in apple land
Dec 7, 2011 01:05
Do you know whether this will work with a network attached storage device that is not a Time Capsule?
Michael Sliwinski
Dec 7, 2011 11:28
I think this method should work with any attached storage - Time Capsule, USB, Network... actually Time Capsule IS a network attached storage, so please give it a try and let us know if it worked, "stuck in apple land" :-)
stuck in apple land
Dec 8, 2011 14:48
me again... This technique *seems* to have worked using my Synology NAS instead of a Time Capsule. One question though - when I attempt to mount the backup image for my Mac using my wife's computer, I am (appropriately) asked to supply the password, without which I am unable to mount the disk. However, when I log into the NAS's homepage on my LAN, it appears that I am able to browse the directories within the disk image without being asked for a password (I have not tried to actually open any of the files though). Does this mean that the image is not really encrypted?
stuck in apple land
Dec 8, 2011 14:48
me again... This technique *seems* to have worked using my Synology NAS instead of a Time Capsule. One question though - when I attempt to mount the backup image for my Mac using my wife's computer, I am (appropriately) asked to supply the password, without which I am unable to mount the disk. However, when I log into the NAS's homepage on my LAN, it appears that I am able to browse the directories within the disk image without being asked for a password (I have not tried to actually open any of the files though). Does this mean that the image is not really encrypted?
Dec 17, 2011 18:41
Awesome! It worked! I had to reboot the macbook in the process because I fiddled with the disk image and time machine complained that it was in use. After the reboot it worked beautifully. My full-disk encrypted macbook now backs up to an encrypted and limited size Sparse Bundle on my Time Capsule. Thanks man, this is the first blogpost that actually contained a readable step-by-step instructions which worked.
Michael Sliwinski
Dec 17, 2011 23:02
Glad this guide of setting up Time Machine secure backups on Lion still works for so many folks here. Thanks for your kind words Rolf! It definitely works for me every single day :-)
stuck in apple land
Dec 20, 2011 20:56
Thought I would pop back in to thank you and to add one more tip based on my experience with this. I tried to set up the TM backup using my MBP connected to the network through the Thunderbolt display (which was connected to my LAN via ethernet), and using the MAC address for the display. This does not work - the correct procedure is to connect the ethernet cable directly to the MBP and use the MAC address for the MBP's ethernet adaptor. This only needs to be done for the first backup - after that, it does not matter how the computer is connected to the LAN (wifi, direct ethernet, or ethernet via the Thunderbolt dispay all work fine). I hope this saves someone else from several frustrating hours.... And thank you, Michael, for this guide!
Michael Sliwinski
Dec 20, 2011 21:15
Great update with another valuable comment to this guide. Thanks for your contribution "stuck in the apple land" :-) Your observation makes sense as the value of your computer's Ethernet address is what Time Machine takes under consideration so the display's ethernet address should not work, that's correct. Later it works whatever network you use. Has been my experience as well. Thanks again!
Dec 27, 2011 20:14
I am using 10.7.2 with a 3TB 4th Gen Time capsule running Firmware 7.6. I tried these instructions including one of the comments that talks about Nruub on Oct. 29th that talks about 'no renaming'. In both cases Time Machine still ignores my MACHINENAME_MAC.sparsebundle bundle and creates a MACHINENAME.sparsebundle file for backups.
Dec 27, 2011 21:07
One other interesting note. I tried renaming one of these TM created spare bundles to Foo as a backup as suggested in some of the comments and it continued using the renamed bundle.
Dec 30, 2011 03:09
Hey Mike, this post is great but I have one question:

Let's say I were to make a limited and encrypted time capsule backup in the way you described. Would there be any problem if I were to do a clean install of my Mac and try to restore from this backup? Would the encryption confuse it in any way?

Jan 3, 2012 00:41
Hey Michael,

just wanted to say thanks :)
I just tried your suggestions and it seems to have worked great as Time Machine saw the disk image and it is currently using it for the first backup - I have reformatted and reset it to factory defaults before doing this.

On a side note, do you know if / how much the encryption affects the backup speed?


Michael Sliwinski
Jan 3, 2012 11:10
I don't see any impact on the backup speed for secure backups. It's there, but it's not really visible. The convenience and security is amazing though.
Jan 26, 2012 11:31
To Michael:
I cannot see the Time Machine drive in disk utilities, or how do I connect using USB (I would prefer network actually)?

To timbo.phillips
I got very far using your method, but not quite there. After your step f (copying the file, this is what I'm getting in the terminal:

usage: cp [-R [-H | -L | -P]] [-fi | -n] [-apvX] source_file target_file
cp [-R [-H | -L | -P]] [-fi | -n] [-apvX] source_file ... target_directory

When I turn the time machine back on , I'm getting an error saying the disk is already in use. Am I missing something?

Thanks. D

Mar 2, 2012 21:53
Hi again Michael,

I upgraded my MB with SSD drive and this method did not work anymore. Turns out that most probably in some point update the Lion's Time Machine started using the ethernet's MAC-address instead of WiFi, at least on this type of machine. Luckily someone pointed out this possibility earlier in the discussion above, surely I would not have guessed this myself.

Also I'd like to point out that my wife's iBook, running latest version of venerable Leopard , is backing up to the same Time Capsule also using this very method. So it seems to be backwards compatible.

Apr 6, 2012 05:27
ok guys, this is what is missing in this tutorial
forget the: "find out the address of your main ethernet card"
instead do the following:
step 1: run a backup to your time capsule.
step 2: as the backup tmp file is created (you will find the file in your time capsule HD).
right click it and go to "show package content" in it you will find the following
copy them (cmd +C)
step 3: stop the backup (click on the time machine icon and then choose "stop back up"
from the drop down menu. + go into your time capsule and erase the tmp.
step 4: now go over the same stages as mentioned by mr liwinski . in stage 2: section a
"save as:" use your mac name (no ethernet or wifi add ons).
after the file is created. go to your time capsule HD, find the new image file, right
click it and go to "show package content". paste into it the 3 files copied in step
step 5: now run your backup again. it should ask you if its ok to use the image file you created.
Michael Sliwinski
Apr 6, 2012 14:31
It's incredible how this small article became a go-to guide on setting up secure Time Capsule backups :-) Ben, thanks for your great comment, it's very geeky but if it works, that's really cool. Tomi, glad this method also works for your wife's iBook. Cool!
Dave Creek
Apr 8, 2012 23:17
Re step 2. Time Capsule doesn't appear in the Disk Utility window. How do I get it to appear?

What does appear is "iMac-Dave.sparsebundle " and within that "Time Machine Backups"

May 8, 2012 08:09
Hi everybody.
I had the same problem: each time TM created new sparcebundle.
Issue was resolved by changing mac-address and name to "Time machine backups"
Which one is really useful I don't know but at the end it works.
Thank you.
May 8, 2012 15:17
Hello, I followed step by step this procedure but now if I want to delete or to rename the backup of an other MAC, I can ... I test for the moment with 2 MacBook Pro, when I map my network hard disk I can see the Time Machine.sparsebundle of the other MAC. I tried to change the name, I can, and I'm sure I can delete it.
If I want to use this procedure for 60 Mac, do you have a solution to protect the time machine image?
May 20, 2012 20:33
How does one know if this process actually limits the size of the .sparsebundle? When I examine the info.plist for two bundles (one made previously for my iMac and one just made for my Laptop) the size for both is still at 2,998,445,457,408 (3TB). I used the original process to create the laptop bundle.

Shouldn't one be able to look somewhere and see the limit for the Laptop's TM bundle?

Jun 15, 2012 00:12
In OS X 10.7 you can also use the command line utility 'tmutil' See for details.

- Create an (encrypted) disk image
- Move it to the location where you want it
- Mount it
- sudo tmutil setdestination /Volumes/{mounted-disk-image}
- Backup now

Jul 11, 2012 18:23
Hello Michael, i've used this method and worked perfectly! The thing is that i moved over the past weekend and had to create a new wifi. I've used the same time capsule that i had, and now i'm trying to do a backup of the same MacBook Pro i did before. The thing is that TimeCapsule can't find my sparsebundle! Any thoughts?
Aug 13, 2012 11:11
I just bought a new 3TB Time Capsule to backup my MacBook Air running Mountain Lion and couldn't get the above to work, so I googled around and found the following simple approach to work reliably instead.

1) Set up a new time machine backup from scratch using the Time Machine UI. Click the encryption check box for an encrypted backup.

2) Initiate your first time capsule backup.

3) Wait until the backup has started and left the initialization phase so that you can see how many MBs that have been backuped.

4) Stop the backup (using the time machine ui) and turn Time Machine off.

4) You should now have the "machine_name.sparsebundle" file in your /Volumes/Data directory.

5) Open a terminal and type (for a 500GB max size):
"hdiutil resize -size 500g /Volumes/Data/machine_name.sparsebundle"

6) Then do:
"chflags uchg /Volumes/Data/machine_name.sparsebundle/Info.*"

7) Turn Time Machine on and restart the backup!

Step (5) limits the size of the bundle to 500GB and will take a few minutes to finish. Step (6) is really important as apparently time machine tries to reset the size to the maximum each time when restarting and by changing the permissions of the Info.plist file you will stop it from updating the size.

Michael Sliwinski
Aug 14, 2012 13:33
Wow, great comment Stefan! I'll give it a go on one of our Airs that already runs Mountain Lion. My "production" Air is still on Lion. Didn't have the courage to switch just yet. :-) Thanks for your comment and letting us know!

Sep 9, 2012 01:19
The good MAC address to use is the one you get in Terminal using the command : ifconfig en0 | grep ether .

Not the one you suggest to pick in Wi-fi address you suggest to pick from system preference. It's not the same and just don't work if you pick this one.

Is it possible for you to update the instructions?


Michael Sliwinski
Sep 10, 2012 12:00
Thanks for the comment, Rene, I'll update these instructions very soon together with instructions for Mountain Lion. Thanks!

Sep 26, 2012 20:07
if time machine keeps "looking for disk..." and ends up not finding it, it may be because disk utility is still open and using the sparsebundle. i had to unmount the volume in disk utility, eject the sparsebundle, eject my time capsule disk, close disk utility and then reconnect the tc disk before time machine could find the sparsebundle. works for me. thanks for the post ^^
Michael Sliwinski
Oct 4, 2012 10:55
I'll update these instructions for Lion as well as these for Mountain Lion later this week. Thanks for your comment! Glad it worked for you in the end!

Gérard Perret
Oct 8, 2012 16:10
Good Morning Michael,

First thank you for this post, very clear and interesting, I am going to try to bring you back my two cents.

I was more than happy when I got my Time Capsule but quickly disappointed when I started to use it with Time Machine. Selecting the maximum size of a backup storage was not possible!! Why a so logical parameter could not be set?? Good news is that I am not alone to be struggled with!!

I have recently upgraded my two Machines, one Imac and one MacBook pro to Mountain Lion.

I have these two machines + my son’s MB saved on my Time Capsule this is the reason why I first selected the method described by timbo_phillips (October 2011) to try to preserve previous backups.

I did a first test with my MB, the backup went well but at the end it prompted saying that the checking was not correct and that a new full backup was required :-(.

So by the way I removed the old sparsebundle file and started with your method creating a 300G image file. I checked the info.plist file and it was set to 307200032768 which looked good to me.

I started then Time machine, called for a new backup and here is the bad thing: TM updates the info.plist file to the full Time Capsule size!!
This is tracked in the system logs: Resizing backup disk image from 307.2 GB to 2 TB

I restarted everything using another method described here (similar to your method),
And I got the same issue.

Finally I did it one more time following your method but in addition I did what Stefan was suggesting on August the 13th but I only set the info.plist file to locked (this lock can be displayed in the properties of the file)

From the terminal: chflags uchg /Volumes/Data/machine_name.sparsebundle/Info.plist

Started again a new backup and here the mounted image is set to a capacity of 307 G and info.plist did not change.
This time logs are showing up a message from TM: Could not resize backup disk image (DIHLResizeImage returned 35) which is great for me

I did a first backup, and at the end info.plist was not modified, I could access to the backup from Time Machine and capacity of the mounted image is still 307Go.

Now I keep my fingers crossed waiting to reach the 300G of backup!!

Nov 19, 2012 22:30
One of the greatest tutorials I've ever used. My timecapsule says thanks. Hahahaha.