frankfromphiladelphia Said:
"[…]when I start it uo the progress bar goes about half across then stops and the computer shuts down. this happens every time I start up the iMac.I tried all of the Key combinations including command r. None of the key combinations work”
———-
Troubleshooting a Mac Stuck in a Boot Loop:
Being consistent? it seems you are in a boot loop. This typically occurs when you were updating, and it got stalled in the process. So, refer to the following...
I. Boot in Safe Mode:
In Safe Mode, Login Items do not run at login, certain preferences are set aside, and damaged system files are then reset. So, once booted in to Safe Mode, wait 30 seconds, and then boot up normally, attempting another update install. For instructions, go here: How to Use Safe Mode on your Mac - Apple Support
II. Reset your SMC and your NVRAM:
(Applies to Intel-Basel Macs Only) Sometimes changes (i.e. Installations) are made to the system and then settings (i.e. Networking) become corrupted, technically. So, reset both on your Mac. So, reset the SMC and reset the NVRAM or PRAM. It might take three tries. to fix this. So, be certain you have the time to do so.
Start With This:
III. Re-Mount the Drive:
Boot into Recovery Mode (Intel or Silicon) . You need to click the “Mount’ button to proceed. So, select the drives, and then click "Mount" Try rebooting once more. If of no success, then click unmount button, and then the mount button. Try rebooting once more. It looks dulled-out. So, if you cannot click it, then click the First Aid button to fix this volume.
