When running a document set to backup, Synk may encounter items in the destination that are not present in the source. Depending on your particular situation, you may want these to be treated in different ways.

You have three options for how these extra items are handled:

• "Leave in place" -- Extra items will be left untouched. This is a good idea, for instance, when you are backing up your entire system to an external drive that is also being used for unrelated storage, and you don't want your other data deleted.
• "Delete if previously in source" -- If Synk has seen the item in the source on a previous run, but it is now missing from the source, then it will remove it from the destination. If Synk has no record of the item previously existing on the source, it will leave the item on the destination untouched.
• "Always delete" -- Synk will delete the extra item in the destination. This will produce exactly the same items in the destination as the source, regardless of the previous state of either folder.

The "Delete if previously in source" option requires information about the previous state of your source folder to be stored in a catalog. Learn more about the catalog.

A similar setting for documents set to Synchronize is the "synchronize deletions" setting. Learn more about the "synchronize deletions" setting.