time machine
After Time Machine finishes backing up my iMac, the words "Cleaning Up" are displayed below the scroll bar that depicts how much of the event has finished. Sometimes this "Cleaning Up" takes several minutes (up to 30 minutes), while other times, it's done after only a few seconds. What is going on behind the scenes when Time Machine is Cleaning Up?
iMac, OS X El Capitan (10.11.6), iMac (24-inch, Early 2009)