In Mac OS X 10.3, 10.4 or later you can rename your home directory without the safeguard of entering your password (authentication). If you do this, your home directory contents and preferences will appear to be lost the next time you log in. Applications use default preferences, and your home directory subfolders (Documents, Pictures, and so forth) are empty.
This issue affects Mac OS X 10.3 or later.
When an "admin" user renames his home directory, a new, empty home directory will be created the next time the affected user logs in. Though the original home directory is not being used, it is still present. This may create the false impression that the home directory is lost.
Note: For technical reasons, it is best not to intentionally change the name of a home directory unless absolutely necessary.
Before you assume that the home directory contents were actually lost, check the /Users folder to see if the missing home directory is present and simply renamed.
If you determine that the home directory is present but renamed, follow these steps:
1. In the Finder, go to the /Users folder.
2. Locate the new home directory, which bears the users' short name.
3. Add "_new" to the new home directory's name.
4. Rename the old home directory to the user's correct short name.
5. Log out and back in with the affected user account.
