macOS sometimes creates files that are hidden in the Finder and may cause confusion when mentioned in a sync error or listed in the sync confirmation dialog.
.DS_Storeand.localizedare system files that can appear inside any directory. It is recommended to exclude these system files with a filename filter or by excluding hidden files altogether..DocumentRevisions-V100,.Spotlight-V100,.TemporaryItemsand.Trashesare system directories that appear at the root of an external device. SyncTime doesn’t have enough privileges to access these system directories. Instead of selecting the root directory as the destination, it is recommended that you create a dedicated directory and select that one as the destination. Alternatively, you can exclude these system directories with a filename filter or exclude hidden files altogether.
Tip: you can toggle the display of hidden files in the Finder with the keyboard shortcut Command-Shift-.
For additional help, see Filters.