Are you drunk on holiday wine and reinstalling OS X on your Mac? This is my procedure for backing up and reinstalling.

Note: This backup/restore process requires manual twiddling during the restore process, and isn’t recommended unless you’re comfortable dealing with that. It takes more active user time/effort than using Apple’s Migration Assistant, but it allows you more fine-grained control; you won’t be porting over applications and settings that you don’t actually use. This assumes you have an external hard drive of some sort; if you have a second hard drive in the computer, instead, that will work just as well.

  1. I manually backup obvious large folders to my backup drive (Such as my iTunes Media folder, my current work documents, etc.) and then delete them from my boot drive.
  2. I search through frequently-crufty folders like my Downloads folder and consolidate them, then move them up to the backup drive and delete from the boot drive.
  3. I reboot, closing any software that auto-launches.
  4. I use Carbon Copy Cloner to backup the remaining files on my boot drive to a disk image on my backup disk. (this step takes a long time. It’s certainly a “Go for dinner and read a book while it happens” step.) I use a disk image because this means I just have one giant file with my backup in it, so it can easily be ignored, not indexed by Spotlight, etc. The settings I use are these (CCC version 3.3.7):
  5. I deactivate all software that needs activation/deactivation (such as Creative Suite.) During this step, I get sad about copy protection and think about all the money I’ve spent on this software.
  6. I download the latest Combo Updater from the Apple site and store it on my backup drive.
  7. I do a full reinstall, formatting the entire boot drive. I dicker with the installation options to not install stuff I don’t need (tons of extra printer drivers, for example.) Please note that even though you have a Snow Leopard ‘upgrade’ disc, it will function fine for a full install.
  8. I run the Combo Updater to bring my install up to the newest version. Reboot. Install all Software Update updates. Reboot again.
  9. I drag over the big folders I backed up in step 1 from the backup drive to my boot drive. I then delete them from the backup drive. (I’ll back them up again later … but at this point, I want to make sure I know what I’ve restored and what I havent.)
  10. I install software that I know needs to be installed from original discs, like Creative Suite.
  11. I mount the disk image that I created, and I slash and burn through it: I open the Applications folder and delete all the Apple-provided applications [Dictionary, DVD Player, etc], and applications that will need a proper reinstall in order to work.
  12. I drag over the applications that I know I’ll need. In some cases I’ll dig around in the preference/library folders and restore all their preferences, as well. Plus stuff like my Keychain (stores passwords), Mail, etc. A few specific examples of which files to restore for which applications are below. Most applications follow similar patterns.
  13. Restoring Keychain: The Keychain is the file on your computer where all your passwords live. It’s at ~/Libary/Keychains/login.keychain and you can just copy the backed-up version overtop the new file that was created in your new install.
  14. Restoring Mail: this is the big one for me. In my disk image, I grab the directory ~/Library/Mail/, and drag it onto the primary hard drive, replacing the default ~/Library/Mail/ directory completely. Then I grab the preferences file from ~/Library/Preferences/com.apple.mail.plist and copy it to the same directory on the primary hard drive. If you had previously installed any mail plugins [such as the workhorse Mail Act-On then you may need to drag their preferences over as well. Then I fire up Mail, and it converts the mailboxes over to the new format, an apparently necessary step even though the version of Mail doesn’t change. After that, I replace the default mail icon with the delicious “Love Letter” icon from Cian Walsh’s iLust icon set.
  15. Restoring Adium: Same process, with the folder ~/Library/Application Support/Adium 2.0 and the ~/Library/Preferences/com.adiumX.adiumX.plist file.
  16. I install printer, Wacom drivers, etc.
  17. This step is optional: After emptying the trash and unmounting the disk image, I use the following terminal command to compact the image:

    hdiutil compact /path/to/Backup.sparseimage

    So, if your external hard drive is named “Ralphus” and your backup was named “Ninja”, the command would be:

    hdiutil compact /Volumes/Ralphus/Ninja.sparseimage

    This command will take a few minutes to run, but eventually it will reduce the amount of space the disc image takes up on your backup drive.

  18. This is more steps than simply restoring from Time Machine, for sure—but I think it’s far better for actually getting rid of cruft you no longer use by identifying and restoring only the things you actually use … and you have a complete backup of the stuff you don’t use, in case you do need it down the road.