Today I had to send in my MacBook Pro laptop for repairs due to a possibly failed logic board. No matter. I was given a loaner by our good tech support people at the College. And I had used Time Machine for my backups. In the span of less than an hour, I was able to restore all my previous data and configurations from the expired Mac to the new one. This evening, I was able to convince Time Machine to continue backing up from where it left off on the old machine — a bit of a trick.
Restoring user data to a new computer
But, I’ll begin these notes at the restore. The loaner laptop had a basic administrative account into which I logged in. To get started, I used Migration Assistant to prompt the OS to use my Time Machine backups as the source of the data I wished to restore. Migration Assistant correctly identified the Time Machine volume (an external Maxtor drive connected via Firewire) and the backup I wished to use. It asked which user I wished to restore, as well as whether I wished to restore previous applications. It also asked if I wished to restore network, time zone, and other configuration preferences. I took what I was offered and I accepted all available backup items. Once I completed these selections, I let Migration Assistant proceed with the restore. The remaining activity of Migration Assistant was unattended. After about 45 minutes, the restore was complete.
On completion of the restore, the loaner laptop had a new account — the identical account I had had on the original laptop. I was able to log in with the user name and password that I had previously used. Once at the Desktop, I found that all items and almost all settings from the expired laptop had been transferred to this new machine. Very, very nice.
There were some small differences worth noting. None of the printers were restored. The International icon on the menu bar, used for selecting the keyboard layout, was reset to the U.S. keyboard and none of my alternate keyboards were available. Thunderbird was acting very strangely the first two times I launched it (in one instance did not display a listing of messages but a list of the folders in the mail account), but was back to normal on the third try.
On resuming backups from where Time Machine had left off
One difference was particularly tricky to fix. Apparently, Time Machine backups rely on the MAC address of the computer to identify the hardware from which it is performing a backup. That means that when I tried to perform a backup from the new laptop, Time Machine would try to do a full backup instead of an incremental backup from where I had left off. As far as Time Machine was concerned, this was a new machine. Indeed, it was. But I wanted it to be treated like the old laptop, as though there were no interruption.
To convince Time Machine to treat the new laptop as though it were the new one, I followed the instructions I found here at the Mac OS X Hints web site. The following summarizes the procedures I followed.
First, I disabled Time Machine by clicking its prominent On/Off button.
Using System Profiler, under Network > Ethernet, I located and noted down the MAC address of the new computer. Next, I noted down the name of the external Time Machine volume and of the computer I wished to backup. Also, I noted down the MAC address used by the original computer using a command issued in Terminal. For this last part, I used the following commands in Terminal.
cd /Volumes/BACKUPVOLUME/Backups.backupdb
xattr -p com.apple.backupd.BackupMachineAddress COMPUTERNAME
I used the name of the Time Machine backup volume for BACKUPVOLUME, and the name of my computer for COMPUTERNAME.
Next, I issued the following series of commands in Terminal.
sudo fsaclctl -p /Volumes/BACKUPVOLUME -d cd /Volumes/BACKUPVOLUME sudo mv .a0a1a2a3a4a5 .b0b1b2b3b4b5 sudo xattr -w com.apple.backupd.BackupMachineAddress NEWMACADDRESS Backups.backupdb/ COMPUTERNAME sudo fsaclctl -p /Volumes/BACKUPVOLUME -e
For .a0a1a2a3a4a5, I used the old MAC address without the colons but with a preceding period. A MAC address a0:a1:a2:a3:a4:a5 would therefore be keyed as .a0a1a2a3a4a5. For .b0b1b2b3b4b5, I used the new MAC address without the colons but with a preceding period, in the same manner as for the old MAC address, already described.
For NEWMACADDRESS, I used the MAC address of my computer, with colons.
Once these steps had been completed, I remounted the backup volumes (ejected them, then reconnected them), restarted Time Machine (big On/Off button back to the On position), and selected the desired backup volume in Time Machine using the Change Disk button.
The next backup that was done took a while, but it was an incremental backup simply restoring its various links.
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Excellent post!!! I always wondered how you’d do this. I hope I won’t need to use this knowledge any time soon, though.
MySQL data was not restored on the first go. I used the instructions found here (http://suburbia.org.uk/blog/2009/05/08/173824.html) to guide me through restoring my MySQL data.
Also, for whatever reason, Time Machine didn’t provide me a way to go into hidden folders. My workaround was to create an alias that pointed to the MySQL data directory. This helped, but Time Machine still seemed a bit flaky when navigating to the desired backup date.