If you were able to use Apple’s Setup or Migration Assistant, this doesn’t apply to you. If you were forced to do a “clean” install to solve serious problems, you may need to do this. This could also be useful if your data was recovered through a scavenging method because your disk directories were a mess.
This is a complex operation and prone to error, which can leave your computer in a dysfunctional state and compromise your data. We highly recommend making separate external backups of both your “new” system and your transferred data before attempting to integrate them. Unless you tend toward geekiness, we strongly suggest getting professional help with this.
The challenge is to get your old working software back without bringing back old problems. Here are some hints:
- Make a backup of your new, working system before you begin bringing back old software. Or keep a system installer disc handy if you’re starting with a fresh operating system.
- Copy as little as possible. It is better to install from downloads of the latest software or original CDs than to copy over your old software. We highly recommend reinstalling all applications from original discs or downloads rather than trying to copy them over. To reinstall software from the Mac App Store, launch it from Applications. Then click the Purchased tab to re-install your software.
- Move only a few files at a time. Test after each move, so you can isolate any problems that may arise.
- Before you replace an existing file with your saved copy, think carefully. In all likelihood you should keep the newer, fresh copy, avoiding possible corruption.
You won’t need to move all your folders into your new system. Here are a few of our favorites:
- If possible, use Import under the File menu in applications such as Mail, iPhoto, and iTunes to get your old data into your current system.
- Most of your preferences will live in the Library subfolder of your User folder. Move those first. In Lion, the Macintosh HD/Users/YourName/Library folder is hidden. To access it, click on your desktop, select Go to Folder from the Go menu. Type “~/Library” into the resulting box. Then select the revealed Library folder and wait a few moments for it to load.
- Some applications store important preferences in either MacintoshHD/Library/Preferences or in Macintosh HD/Library/Application Support, so move those as well.
Here's a rundown of where Mac OS X stores your Application and iLife data:
|Mail data and settings||Macintosh HD/Users/myname/Library/Mail/|
|iTunes data and settings||Macintosh HD/Users/myname/Music/iTunes Music/|
|iPhoto data and settings||Macintosh HD/Users/myname/Pictures/iPhoto Library/|
|Address Book data and settings||Macintosh HD/Users/myname/Library/Application Support/AddressBook|
|iCal data and settings||Macintosh HD/Users/myname/Library/Calendars/|
|Safari data and settings||Macintosh HD/Users/myname/Library/Safari/|
|Keychain data and settings||Macintosh HD/Users/myname/Library/Keychains/|
|Other preferences||Macintosh HD/Users/myname/Library/Preferences/|
Additions to System Preferences are often in Macintosh HD/Library/PreferencePanes. These are frequently incompatible with new versions of the OS, so now is a great time to check www.download.com or the Mac App store for updates. You should NOT move these, but rather reinstall from original or updated installers.
Applications infrequently put invisible but important applications in Macintosh HD/Library/StartupItems. This is uncommon enough that you may not have that folder at all. But again, we suggested reinstalling all applications from their original discs or downloads, not trying to copy them over. So don’t copy these either!
We strongly recommend against copying kernel extensions or anything else from your old Macintosh HD/System folder, since they may not be recognized by the new system and could get you in big trouble.