03/30/2009 13:02 by mud ()
I recently sent my MacBook Pro to the Apple Store for repair, and it came back all fixed up. A new display for the backlight banding problem, a new top case for a failing keyboard and a new logic board for replacing the nvidia card. I have a Lacie 2Big Triple that I use as a Time Machine backup for this computer, but I realized the backups kept failing.
Time Machine apparently uses your MAC address to keep track of which machine your backup corresponds to. So of course if you get your logic board replaced, you’ll have a new MAC address and Time Machine will think this is a different computer.
I did some google searching, but this method did not work for me. I had to combine this other method to make it all work. Anyway, here’s the list of what you have to do. First, make sure you go into System Preferences and turn off Time Machine. Then fire up the Terminal and run:
$ cd /Volumes/NameOfTMDrive/Backups.backupdb
$ xattr -p com.apple.backupd.BackupMachineAddress NameOfMac
This should spit out your old MAC address. In the backup drive, you will have a hidden file with the values of this MAC address. Now, look up your new MAC address with:
$ ifconfig en0
Write the new MAC address down. What you will now do is rename the hidden file from the old MAC address to the new one, then tell backupd your new MAC address. In this example, your old MAC address is aa:bb:cc:dd:ee:ff and new address is 00:11:22:33:44:55, and your computer name is My Computer. We also turn off ACL and turn it back on after we make the changes.
$ sudo fsaclctl -p /Volumes/NameOfTMDrive -d
$ cd /Volumes/NameOfTMDrive
$ sudo mv .aabbccddeeff .001122334455
$ cd /Volumes/NameOfTMDrive/Backups.backupdb
$ sudo xattr -w com.apple.backupd.BackupMachineAddress 00:11:22:33:44:55 "My Computer"
$ sudo fsaclctl -p /Volumes/NameOfTMDrive -e
Now, you just need to remove your drive, then remount it. Go into Time Machine, and turn your backup back on. This will start indexing your drive again and for a long while, it will say “preparing…” It took my computer about 20mins to complete the initial backup. If it begins creating a new backup with “My Computer 2″ you did something wrong because it’s starting a new backup.
Apple should probably make this easier since I’m sure a lot of people are going to have their nvidia cards replaced.
April 17th, 2009 at 05:46
Hi – just got my MBP back, also with a new logic board, and have the same issue. however i’m stuck on the first step. i can cd to the backupdb just fine but when i try to run:
$ xattr -p com.apple.backupd.BackupMachineAddress
nothing happens. i should be seeing the mac address, right?
Any ideas?
Thanks in advance!
n
August 3rd, 2009 at 11:14
Okay, so I’ve tried many variants of this and cannot get it to “spit out” my old MAC address. One concern I have is that I have two computers backed up to this hard drive. Perhaps I need to change the syntax to get it to show me the one I want…? Right now, the xattr -p com.apple.backupd.BackupMachineAddress command just returns the $ cursor. Help!
August 3rd, 2009 at 11:31
Something might have changed with how Timemachine keeps track of volumes, but you should still be able to see your old MAC address by:
cd /Volumes/NameOfTMDrive
ls -la
The file that looks like .XXXXXXXXXXXXXX (eg. .1a2b3c4d5e6f) will imply that your MAC address is 1a::2b::3c::4d::5e::6f
August 6th, 2009 at 20:49
Cheers for your efforts but I can’t get passed the first step :S
cd /Volumes/NameOfTMDrive/Backups.backupdb
for me is:
cd /Volumes/Backup HD/Backups.backupdb
I enter this into terminal and get ‘no such file or directory’ in response
I’ve got the external hard drive attached and can’t think of any stupid mistakes i’m making.
Any help?
December 15th, 2009 at 01:28
Thanks for the writeup. I was able to get it to work, with a minor change. (For those having problems with spaces in path names – double quote the whole path or backslash each of the spaces.) In my case it would not recognize my computer name, even if I cut and pasted it from the filesystem into double quotes. However, I was able to simply wildcard the computer name with an asterisk (*), and since I only have one system name in the folder, it worked. I did need to cd back into the Backups.backupdb folder before the 2nd-to-last step, and wildcard it there as well.
But I now have a working Time Machine again, it did not need to back up the whole system (the “preparing” finished after about 10-12 minutes), and I can browse through 18 months worth of previous backups.
January 12th, 2010 at 10:19
I get the following output, nothing with the old MAC address:
drwxr-xr-x 8 Sachit staff 476 Dec 21 2008 .
drwxrwxrwt@ 6 root admin 204 Jan 12 20:40 ..
-rw-r–r–@ 1 Sachit staff 6148 Jan 12 19:55 .DS_Store
drwx—— 3 root staff 102 Apr 8 2008 .Spotlight-V100
drwxrwxrwt@ 3 Sachit staff 102 Apr 17 2008 .TemporaryItems
d-wx-wx-wt 3 Sachit staff 102 Jan 12 20:40 .Trashes
-rw-r–r– 1 root staff 0 Apr 8 2008 .com.apple.timemachine.supported
drwx—— 2 Sachit staff 4522 Jan 12 20:40 .fseventsd
drwxr-xr-x 3 root staff 102 Apr 8 2008 Backups.backupdb
drwxrwxrwt 3 root admin 238 Jan 12 19:58 lost+found
btw you can also get the old mac address from the sparsebundle image name in the end
old one was 001f5bf1441c and new one is 001ec2c1adde
any help would be greatly appreciated
January 28th, 2010 at 19:23
Hi Guys,
A couple of comments.
One try using tab key to auto-hint/auto-resolve your paths, also in terminal you can not use names with spaces for paths, so either comment out spaces with \ or enclose the whole path in quotation marks:
eg.1: foobar$ cd /Volumes/My\ Backup\ Drive/Backups.backupdb/
eg.2: foobar$ cd “/Volumes/My Backup Drive/Backups.backupdb/”
Also there is a mistake in the above instructions. At **
$ sudo fsaclctl -p /Volumes/NameOfTMDrive -d
$ cd /Volumes/NameOfTMDrive
$ sudo mv .aabbccddeeff .001122334455
** Change to the Backups.backupdb folder first or include the whole path in the next command.
$ sudo xattr -w com.apple.backupd.BackupMachineAddress 00:11:22:33:44:55 “My Computer”
$ sudo fsaclctl -p /Volumes/NameOfTMDrive -e
Great article otherwise BuzaMoto!
John.
January 28th, 2010 at 19:28
@john
You’re right. Updated the post. Thanks!
-Tak.
March 10th, 2010 at 09:46
Thanks, this worked for me. One note, however, instead of “My Computer” which shows up on my desktop as “Macintosh HD” Time Machine uses my username “Kyle XXXXXX (MBP17)”. Other folks might have figured this out no problem, but just a heads up.
Kyle.