How can I create a backup of SyncTime itself?

If you only want to keep a copy of the sync items and their settings (the ones you can change in the settings window), you can export them from the File menu or the main window context menu (which you can open with a right-click). This is the preferred way of saving the sync settings when you are planning to install SyncTime on a new Mac and want to import the sync items again, knowing that the syncs from the old Mac are up to date and the internal snapshots used by SyncTime to track the state, if any, can be automatically recreated on the next sync.

Snapshots are only created for sync items of type two-way, if the option to track moved files is enabled, or if it contains a filter expression that creates symbolic links. Snapshots are saved along with the activity logs in

~/Library/Containers/org.desairem.uSync/Data/Library/Application Support

where ~ is your user directory. The directory named org.desairem.uSync is displayed by the Finder as SyncTime on recent versions of macOS.

The app preferences, including the sync settings, are saved in (according to macOS standards)

~/Library/Containers/org.desairem.uSync/Data/Library/Preferences/org.desairem.uSync.plist

If you want to back up these files, you can create a sync item with the enclosing directory as the source:

~/Library/Containers/org.desairem.uSync/Data/Library

Any other files in this directory are symbolic links created automatically by macOS and can be excluded. To exclude everything except for the paths mentioned above, you can add the source as an explicitly excluded file, then add the paths above as included. Please refer to Filters for more information about this technique.

When replacing the app preferences file, you need to restart your Mac before it is correctly read. Also, please note that manually replacing the snapshot files but importing previously exported sync items (as opposed to also replacing the app preferences file) won’t work, as the IDs of the imported sync items will not be the same as the ones referenced in the snapshots.

If you created any custom user scripts differing from the ones available by default in SyncTime, you may want to back them up as well. They are located in

~/Library/Application Scripts/org.desairem.uSync