I do most of my writing on a Late 2012 Mac mini that I try to keep relatively sandboxed from all of the blithe experimentation that goes on with my other devices. Consequently, error messages are a very rare sight on my Thunderbolt Display. So, I was a bit surprised by the kernel panic that occurred immediately after I upgraded to El Capitan, and even more so that it happened every single day after that.
When shutting down, the Mac mini reliably threw a kernel panic (where you see a message box in the middle of the screen and the same sentence in lots of different languages). After an
I was surprised by the kernel panic that occurred immediately after I upgraded to El Capitan
automatic restart, shutting down again immediately from the login window works normally, but not if I log in first.
OS X generates a crash log when it restarts after a kernel panic and offers to send it to Apple. The first couple of times I just sent it, unthinkingly, and got on with my day. But as the problem persisted, I began adding background info in the comment field. Eventually, I bothered to read the details in the log itself. The process that was crashing was always related to IOUSB Family, so I decided to unplug my USB devices. As it turns out, I only have one – an old five-port hub. The moment I unplugged it, the Mac mini crashed. So case closed, I guess. Time for a new USB hub.
Moral: The crash log does actually contain useful clues.