Rebooting desktop iMac
I try to fully reboot my computer and when the disc utility screen comes up I run First Aid but after trying to restart it goes back to the disc utility screen and cannot go beyond that screen
iMac 27″, macOS 10.13
Attempt the following
Please restart the computer in Safe Mode per the directions in the How to use safe mode on your Mac - Apple Support link.
Note: If you are using a wireless keyboard please either plug it in using the supplied Lightning cable that shipped with it. If you are using a legacy keyboard or a third-party keyboard that does not have re-charging abilities, please use any USB keyboard. Also note that a Safe Mode restart may require you to hold down the shift key for up to 5 minutes before the computer starts in Safe Mode. You will know it is in Safe Mode when you see “Safe Mode” in the upper right of the display.
Next, please restart normally and please retest.