iMac only booting half way
My iMac boots up half way then shuts down
My iMac boots up half way then shuts down
Likely a hardware failure, however please do the following:
How to reset NVRAM on your Mac
Use safe mode to isolate issues with your Mac - Apple Support
If both fail, then the next step is to locate an independent Apple Authorized Service Provider and to take it in for service.
iMac only booting half way