iMac (OS High Sierra 10.13.3) keeps restarting few times per day

[Ben777]

I couldn't find any decent answer on internet on this one.

My iMac (25 inch, late 2012) keeps restarting on its own. This is annoying, especially if you are in the middle of working.

Does anyone know the reason?

Thanks!

 

[Fishrrman]

Have you added RAM (other than factory-installed)?
Or... changed out the RAM?

 

[Ben777]

Have you added RAM (other than factory-installed)?
Or... changed out the RAM?

No, the RAM stays untouched for the last 3 years. In all other respects this iMac runs perfectly, except for the rebooting problem.