Unable to Enter Time Machine on OS X 10.11 El Capitan

I recently upgraded my iMac 5k to OS X 10.11 El Capitan, and one of the few problems I’ve run into is that the Time Machine UI wouldn’t work. Time Machine itself was working fine – my files were being backed up; I just couldn’t get into the UI to browse the backups.

Looking at the system logs in Console.app, it was obvious that the Finder was crashing as soon as the Time Machine UI tried to launch:

Finder[23082]: An uncaught exception was raised
Finder[23082]: *** -[__NSArrayM objectAtIndex:]: index 0 beyond bounds for empty array
Finder[23082]: *** Terminating app due to uncaught exception 'NSRangeException', 

After a bunch of Google searches, I found this thread on the Apple support forums which provided the fix: if you have multiple monitors, either unplug all but your main display, or turn off “Displays have separate Spaces” in the Mission Control system preferences.

Screenshot

After turning that option off and logging out / logging in, the Time Machine UI works great. Hopefully, Apple will fix this in 10.11.1.