How to change Time Machine settings of a partly broken OS (e.g. by manipulating configuration files)

Question

I have a broken Mac OS 10.6.8 here.

• Startup is normal, login works, but most programs can't be started
• Repair of OS with install disks fails
• Backup via Time Machine is working
• System Settings cannot be accessed

So I have a working backup and want to erase the harddisk to make an installation of 10.7 possible. The problem is, that the backup does not incorporate all files and folders I need. This is due to the settings excluding some folders. Is there a way to change the excluded folders manually?

I'm fine with a hint where to find the configuration files for Time Machine, so I can change them with an appropriate Editor.

Answer 1

The folders or paths excluded from the Time Machine backup are stored in /Library/Preferences/com.apple.TimeMachine.plist

To include them again modify the file with an editor (TextEditor will not work) or sudo nano /Library/Preferences/com.apple.TimeMachine.plist and remove all entries in the SkipPaths array. In the example below you'd have to remove line 19 to include the (excluded) /Applications folder again.

You then probably have to restart the backup daemon.

If you don't have access to Terminal or an appropriate editor, copy the files and folders manually with the Finder to the backup volume and copy them back after installing the new operating system.