Damaged preference files are a common cause of problems for programs running under Mac OS X, as well as the system, itself.
For Mac OS X it is often handy to have a second user (create one using the "Accounts" preference pane under Mac OS X 10.2 and later). If you log out and log in as the second user you might find a problem disappears. In this case it might be because of a user preference being damaged. Because most preferences are stored separately for each user under Mac OS X, logging in as another user will use a different preference file (a default one if that user hasn't used the program before).
In this case try logging back in as the original user and trashing the appropriate pref file. Note that prefs for modern Mac OS X programs are often named with a sort of "reverse domain name", for example Finder prefs are stored in the file "com.apple.finder.plist". If you have the developer tools installed you can open this file using "Property List Editor" and check it. You can also open it with any text editor (or word processor) and edit the XML by hand.
If changing the preference file doesn't help there might be another component installed specifically for that user. You should look in the user's "Library" folder for the usual suspects! If all else fails, create a new user, move the documents into that user's folder and remove the old one.
Mac OS 9
Older systems (such as 9) also seem to be affected by damaged preference files. Its worth disabling the preferences (move the Preferences folder out of the System Folder and restart) to see if unexplained problems disappear. If the problem goes away move as many preferences as possible back into the new preference folder before trashing the old one.
TIPS PAGE