Turn on Do not remove any accounts if you want to keep any accounts in ProjectWise that would have otherwise been removed, due to the deletion of the respective account(s) from the Windows domain or Active Directory.

or

Turn on Remove deleted accounts (NT4 domains only) if you want to remove any accounts from ProjectWise whose respective NT4 domain account was also deleted. If this setting is on, you must also specify what user will take ownership of the deleted user's documents and folders.

or

Turn on Remove accounts that are not synchronized anymore if you want to remove any accounts from ProjectWise which are out of synchronization (and cannot be synchronized) with the respective Windows domain or Active Directory account(s). If this setting is on, you must also specify what user will take ownership of the deleted user's documents and folders.