Selecting all folders automatically selects all the files and/or folders under Outlook, OneDrive and Personal Site of the selected Microsoft 365 user account. And all the files and/or folders under Teams, SharePoint Sites and Public Folders of the Microsoft 365 organization.

DSC is not required when all the folders are selected for back up. As during a backup job any deleted files in the backup source will be automatically moved to Retention Area.

Below is a sample screenshot of the backup source with all folders selected.

When not all folders are selected for backup and folders are subsequently un-selected from the backup source. The backup job will not pick up the changes of the de-selected folders, they will not be moved to the Retention Area but remain in the Data Area. In the long run this could result in a build-up of data in the backup destination(s).

DSC is highly recommended to synchronize de-selected folders in the backup source with the backup destination. This will ensure that there will be no data build up on the backup destination(s).

Below is the sample screenshot of the backup source with selective folders.

On the sample backup log, it shows that DSC is enabled and runs for the first time.

On the sample backup log, it shows the countdown until the next DSC which is in two (2) days.

On the sample backup log, it shows the countdown is done and DSC is running.

On the sample backup log, it shows that DSC is disabled.