This always catches me out. I never remember what they all mean so though i would create a quick help guide to remind me and possibly help you out too.
So whether you’re using Group Policy to map a drive, Schedules Task… you will need to choose the action.
So under the action drop down, you have four options: Create, Replace, Update, Delete
Create – If N doesn’t exist, then create it. If already exists don’t do anything! So basicly it won’t overwrite anything you already have, could be an issue if you decide to update the settings later.
Replace – Remove N if already exists, and create a new N with these settings. If N does not exist just create it with your settings. In short, whether N existed or not you’re getting it. If you have settings that you wish to keep and just want to add, then update is what you need to select. But could be an issue later knowing exactly what settings a user is actually getting as they might not match exactly the GPO.
Update – If N exists it will be updated with the new settings. If there are other settings associated with the drive mapping that aren’t specified here, they will be maintained. If N doesn’t exists create it. Nothing gets removed like with the Replace setting, but there is still a chance that you’ll overwrite something.
Delete – If that drive mapping exists, it will be removed. If N doesn’t exist it won’t do anything.
Personally i would almost always use replace. The setting i apply are the ones i want the user to have, i don’t want to be debugging a computer because i used update and legacy settings are being applied still.
Hope this help someone.