Monday, July 22, 2013

Clean Install of Mac OS X Mountain Lion: What to bring with you

I just did a clean install of Mountain Lion. To my surprise, it turned out mostly OK! (Pro Tip: save yourself the trouble and use Lion DiskMaker, which also works with Mountain Lion.)

It's been documented in plenty of places on how to do it, but the question arises once you've done it: what if there are some settings I want BACK? Like... once I download an app, I want all the same settings back since it's one of those old-fashioned apps that doesn't sync with the cloud... (and even if it does sync, there's still settings and stuff you need.)

Well, you're in luck!

All you need to do is copy the following folders to somewhere safe (external hard drive, for example):
  • ~/ (that's your home folder)
  • ~/Library/Application Support
  • ~/Library/Keychains
  • ~/Library/PreferencePanes
  • ~/Library/Preferences
The tilde (~) represents your Home folder. To get to the ~/Library folder, just open a finder window and issue Command-Shift-G on your keyboard. Then, paste in ~/Library/ and copy those four folders to a safe location.

Once your clean install is complete, I'd recommend re-downloading apps from either the Mac App Store or the app's web site. From there, copy the app's folder in ~/Library/Application Support over to to your Mac's hard drive (same location of ~/Library/Application Support) and then open the app. In most cases, you'll be looking at your app just as you left it last time before the clean install.

Let's walk through an example, assuming you've already saved those folders mentioned above to an external hard drive.
  1. Download ABCApp from
  2. Install it. (Typically just dragging the icon into the /Applications folder
  3. Copy the old ~/Library/Application Support/ABCApp from your external hard drive to its new home on your Mac's hard drive at ~/Library/Application Support/ABCApp
  4. Launch ABCApp
In most cases, you'll be looking at the app just as you'd left it. There are some cases where apps store things in other folders like ~/Library/Preferences (usually .plist files that the app uses) so it might be wise to check both the Application Support and Preferences folders before launching the app.

As part of the clean install process, I also found it helpful to take screenshots of the following, before I blew everything away so I can remember all the awesome shit I use that makes computing wonderful:
  • Dock
  • Applications folder
  • System Preferences screen (some apps I use are actually preference panes)

Hope that helps!