El Capitan stuck on install On a work iMac 27" Intel i5 that wouldn't boot when I got it. Did a restore to Yosemite. Tried to install El-Capitan, which didn't go well at first (I would download it and then get a message telling me it was corrupt when I tried to install). This morning, I re-downloaded and the install kicked off (progress!). However, it stalled and now shows the grey apple and a progress bar (about 95% completed). It's been like that for hours. 

I tried to re-start but it goes right back to this screen. I ran disk utility, but nothing came up.

I'm not a mac user, so I'm not sure what steps to try next. Do I need to do another restore to Yosemite?
Apple Support: 1-800-275-2273 (Or you can get it from here)

Call, it wont take long, and you don't need to have applecare or anything like that. And this way, if something breaks, maybe you'll be eligible for some kind of reimbursement.

You can do the whole thing with your phone on speaker. I actually tried to call them myself (and then relay the information) but one of the first things they ask for is a serial number. 

The occasions i've called them are all blurred together, but i vaguely remember being told to hold the power button for some specific length of time, holding some key while it started up (which might have been to activate disk utility), and unplugging the iMac. 

The key thing, though, is that i called them, it didn't take long, and in doing so i was able to fix it.