Below problems occurs after update installation of new OS Ventura through "system setting".
The OS Ventura was downloaded and installed smoothly/automatically, then after completion the iMac turned on successfully. But the day after that I turned On mentioned iMac device but the iMac faced with unexpected re-start.
After re-starting again the device turned-on successfully but after few hours again faced with unexpected restart.
Unfortunately after the last unexpected restart, the mentioned device couldn't be able to load the OS completely and only show me auto restarting with apple logo in center of the screen.
based on apple suggestions I tried to restore the device but still no result.
FYKI;
no restore available
no boot option appears
....
please advise on an urgent basis.
thanks