SyncTime syncs the source with the destination. It does not sync the source with the file inside the destination that has the same name as the source. That’s why the source and the destination need to have the same type: they both need to be either directories, packages or regular files.
If you want to sync a directory, you can easily create one on the destination from inside the Open panel by clicking the New Folder button. If you want to sync a regular file or package, you need to copy it manually to the destination first so that you can then select it in SyncTime.
Photos Library
In a sync that contains your Photos Library, during the sync you’ll be asked by macOS if you want to grant access to it. If you deny access, the sync will add a permission error to the log and continue syncing the remaining files.
You can enable access to the Photos Library again by quitting SyncTime, then opening the System Settings app, navigating to Privacy & Security > Photos, and enabling the switch beside SyncTime.
