This is based on a technique presented by the wonderful Belgian FCP expert Ronny Courtens, who is often found on the excellent fcp.co forum.
When users start to have problems with their system or FCP, especially when they see sluggish performance for no apparent reason, one of the most commonly recommended test procedures is to create a new user and test it. Why do this? User directory corruptions are often a cause of problems, and because FCP is so closely tied to the OS, the application can be affected by user problems at the OS level separate from the application itself.
You might hear the suggestion to reinstall the OS, but this seldom is of value because the problem really isn’t in the OS itself, but in the user specific directory. Sometimes a complete wipe of the drive and reinstall is useful, especially when moving to a new operating system, for instance when moving from Mavericks to Yosemite.
If you do create a new user and the problems don’t appear in the new, clean user; the application performs well, plays back correctly, imports and exports correctly, then the problem is most likely with the original user. What can be done about this?PersonallyI edit in a separate, dedicate user, who doesn’t sure the Web, send emails, chat, torrent, stream, or download. This user does nothing but FCP, Compressor, Motion, and Pixelmator.
If the new user test works, what you should do next is to rebuild the existing user account. You can do this without wiping the drive. It can be a little scary, but it doesn’t take very long to do.
1. Go to System Preferences>User & Groups and unlock it.
2. Click the + in the lower left to create a new admin user account. Do not use an iCloud password. Use a separate password or no password. This is only a temporary account and can be discarded after the procedure, but first you have to log into this new account so you can work on the other accounts.
3. Next you’re going to delete the problem account and then rebuild it. To make sure you can bring back the original home content it’s critical that you make a note of the exact full user name as well as the short name that appears in Users folder of your system.
4. Select the problem user and click the - button in the lower left. A dialog appears asking what to do with the home folder. Make sure you clickDon’t change the home folder. Then click Delete user.
By doing this you’re removing the user from the system directory, but keeping the user content on your computer.
5.Next, go to the Finder and in Users find the deleted user, which will be labelled like this:
It will appear with the short user name followed by (Deleted).
6. In the Finder remove the parenthetical tag (Deleted). You’ll be asked for your admin password to do this.
7. Now you need to rebuild the account. In Users & Groups click the + button to make a new user. In the dialog sheet enter the original user name, both the long name and the short name you made a note of, and click Create User.
Because the user names are identical, the OS should connect automatically to the existing user folder with the same name. You may get a dialog asking if you want to use the existing home folder or Cancel. Click on Use Existing Folder.
That’s it. Your user folder has been rebuilt in the system directory and should perform much better for you.
