Sync Checker is a diagnostic application which can check if two folders or disks are perfectly synchronized, i.e. if they have exactly the same contents. When creating backup copies of valuable files, or when making sure that two computers or mobile devices work on the same set of data, the status of being "in perfect sync" can be very important. In order to be safe and to prevent loss of data, you can let Sync Checker verify whether a pair of file collections are matching exactly or not.
Note: Now requires OS X 10.12 or later.