- Nov 20, 2017
Why does Time Machine occasionally unmount from my iMac after startup, and how can I prevent that? "Get Info" shows that on its 1.2 TB drive, Time Machine has used 515 GB out of an available 684--does that have something to do with it? I can go into Disk Utility and re-mount it. Still, why does it unmount and how do I prevent that?