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Set all user rights to read access: When this option is selected, all users in the database will default to read only permissions. Note that this does not remove admin rights on users.
Update roles: Updates predefined roles.
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Vacuum- Reclaim disk space, similar when a computer goes through a defragmentation process to consolidate data on a drive.
Remove all files all on disk and file references in the database- Removes all files from database and any file reference that has been carried over from a copied database.