iMac only loading so far
When I turn on my iMac, the screen turns on and it makes the usual chime. The loading bar starts to move, but when it gets about half way it gets slower and slower, then the computer turns off completely.
P.S. Might be worth mentioning that it is a boot-camped iMac and the Windows partition is working fine.
iMac with Retina 5K display, macOS High Sierra (10.13.2)