A while back I was forced to go from OS X 10.10 (Yosemite) to 10.11 (El Capitan) in order to install Photoshop CC 2016.5 I didn’t want to do this as El Capitan a.k.a. El Crap is loaded with bugs. Against my gut feeling I did it.
Today I found a new El Crap bug. I shut down my iMac when the electrical power failed due to a storm and the iMac was running on my CyberPower UPS. The power came back on shortly so I restarted, and I did not see the icons for my two external drives. They were powered up (lights on). Finder did not list them either.
I started terminal and entered:
cd /volumes ls
and there they were! I went to one of them and was able to navigate directories, see files, etc using terminal. So the volumes existed and were intact.
OK, how to get Finder to see them? Go to the Apple icon on the left edge of the menu bar, click it, pick “force quit”, select Finder. The Force Quit button changes to Relaunch. Press it and Finder relaunches (btw it’s not possible to kill Finder). The volumes mounted and seem OK.