When re-installing OS X and importing using Time Machine, which imports should I avoid?

Question

My computer has been having several problems related to hanging and poor graphics performance. I want to re-install OS X to get a completely clean system. I want to keep my files, so I'm going to use Time Machine to restore them. Here are the questions I have:

• Can restoring my Applications folder cause hanging/performance problems to persist?
• Can restoring my settings cause hanging/performance problems to persist?
• Will restoring all these from Time Machine still give me a clean system, or will it make no difference?
• Can I get a similar result simply by creating a new user account on my computer and restoring settings from Time Machine?

I'm running OS X Mountain Lion on a Retina Macbook Pro.

Answer 1

You're talking about two different ways of interacting with a Time Machine backup: restoring and migration.

Restoring from a Time Machine backup essentially makes your computer identical to the state of that backup, with some caveats. Performing a restore from a restoration partition or from a disk will not give you a clean system. You will have all of the same problems that you had when you last backed up.

Migrating from a Time Machine backup will take certain parts of that backup and move them to a freshly installed system. Migrating will let you retain a clean install, but there is always the chance that what you migrate over was the problem in the first place. No matter what you choose, there can always be problems. From my personal experience, however, I can say that the things that are both least essential and have the most potential to cause problems are "Settings" and "Other Files and Folders".

To answer your specific questions regarding graphics hanging and performance, the best option you have is to migrate your user folder, see if the problems persist, and then migrate your applications. You won't be able to create a user and then migrate to that user later - the migration will just create a new user when you try to migrate. The "Settings" are actually just system settings, network settings/profiles, and printers - in other words, nothing that has anything to do with your user account.

Sorry if that answer was a bit rambly. ;)

Answer 2

Restoring everything probably wouldn't fix the issues.

Copying /Applications/ is probably safe. The application bundles themselves aren't usually modified. All settings and cache files are stored elsewhere, but the applications will create fresh ones the next time they are opened if you copy only the application bundles.

I don't know if the Applications option in Migration Assistant also includes support files though.

I have always copied files manually without using Migration Assistant. Create a new account, go to /Volumes/Time Machine/Backups.backupdb/<computer name>/<date>/<drive name>/ in Finder, and copy all user folders (except ~/Library/).

App Store applications might be best to install again (see this question). Other applications can usually be copied manually, but you might need to enter the registration information for some of them again.