Profile in use

Why does the Profile Manager say my profile is already in use when I start Mozilla?

When Mozilla is in use, it locks the active profile to keep other programs from altering the contents. This lock is normally transparent to the user, but sometimes the profile remains locked when it's not expected.

This problem can occur for a few different reasons:

1. Mozilla may not have shut down completely the last time it was used. Check for any open windows. On Windows computers, run Task Manager (Ctrl-Alt-Delete) to see if the mozilla.exe process is running. Ending that process should unlock the profile.
2. Netscape 7 or another Mozilla-based program may be using the profile. Shut down this program to unlock the profile. Additionally, you should create separate profiles for each different application. With Netscape 7 especially, corruption can result from sharing the same profile between two different programs.
3. Mozilla may have shut down abnormally, leaving the lock in place. To fix this, find your profile and delete the file named "parent.lock" (Windows) or "lock" (Linux). This file contains no information, and deleting it will unlock the profile.