OS X won't start anymore

[Jz75]

Hello,

I have an iMac that wont start up anymore. You can see it trying to load the OS, with the apple logo and loading bar. However it stops midway and powers off.

What I did prior to the problem: I reinstalled Yosemite and transferred files from my TimeMachine backup into my user folders (Images, Downloads, Documents etc), as well as photos from an SD-card.

When I restarted the machine the problem presented itself.

Is it possible that copying corrupted files can cause this?

 

[markfc]

It physically powers off?

 

[Weaselboy]

Okay... so you updated to Yosemite and it worked fine after that and the issue started after to moved some things over from Time Machine??

 

[JohnDS]

Reboot while holding down command-r. Then select the utilities menu and go to First Aid. Run Repair Disk.

Then see if it will reboot normally.

If not, the reboot a second time holding down command-r and this time select Reinstall OS X.