Correct File Permissions
Sometimes, file permissions go bad and leave 'locked' or 'used' files behind. If this happens to your DEVONthink Pro database, the application will continue to claim that the database is in use. If you are savvy with file permissions, use either the Finder's Info panel or the Terminal to correct them. Make sure to adjust the permissions of all files in the package. A trick that also seems to work in some cases is to duplicate the database in the Finder and open the copy instead.