Updated iMac to El Capitan, now have black screen

glitch · 10 Dec 2016 at 15:59

For reasons which I still don't fully understand, I felt a sudden urge to update my old iMac to a newer version of OS X, so yesterday found me sticking El Capitan on it and up until I switched it off, all was well.

Today however, I am greeted by what, according to the internet, appears to be a familiar problem - a completely black screen. The iMac 'chimes' on startup, the HDD is clicking away merrily, the keyboard allows me to engage Caps Lock but the screen is black - or to be more accurate, blank. There's nothing on it whatsoever.

Any ideas how I can start to troubleshoot this? I've tried resetting PRAM (goes through the motions just fine, but achieves nothing of note), booting into Safe Mode (ditto) and generally shouting at it (satisfying, but unproductive) and yet I'm still here, staring at a black screen.

beachBOYken · 10 Dec 2016 at 16:06

Any reason you went for El cap over the newer and personally much more stable Sierra?

glitch · 10 Dec 2016 at 16:13

The iMac isn't compatible with Sierra - EC only.

An Exception · 22 Dec 2016 at 21:20

Try to login blind. If you can the black screen should be fixed. If you have another mac you can use screen share to see where you should be typing if you have screen share enabled. If not keep clicking where you think the box should be and type your password. Eventually you should get in.

Biz.Kid09 · 22 Dec 2016 at 22:34

Tried to reinstall EC? Perhaps something got corrupt, see https://support.apple.com/en-gb/HT201314

Emlyn_Dewar · 23 Dec 2016 at 00:19

If you hold the alt key at boot, does it show the boot menu?

glitch · 19 Mar 2017 at 13:12

Just in case anyone was having sleepless nights over this... turned out to be sheer rotten bad luck and the GPU had gone pop. Had to make a decision between replacing it and finding something to replace the iMac with and have ended up going down the route of the latter - just need to find a Mac Mini with the right specs!