rcmj14 Said:
"Startup fails: [...]When I start up by pressing option during boot up the startup disk shows up but when I select it the computer hangs at the Apple logo."
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Mac With an Apple Logo at Boot:
Learn from This:
First off, learn from this, knowing to always backup your Mac every so often, so that you a have something to restore your Mac from, for instances such as this.
So, Three Things...
A. See this Lin: If your Mac Starts Up to an Apple Logo or Progress Bar - Apple Support
B. Updating in Safe Mode:
(Hold Down: the shift key upon boot). In Safe Mode, login items do not load at log in, certain System Preferences are set aside, and damages system files (caches) are fixed.
C. Re-Mount the Drive:
Boot into Recovery Mode (Intel or Silicon) . Then, using Disk Utility, see if the Hard Drive is seem. If it is, then see if you need to click the “Mount’ button for it. Try rebooting once more. If of no success, then click unmount button, and then the mount button. Try rebooting once more.
D. If Neither of the Above Works...
Reinstall the macOS:
Go Here: How to Reinstall macOS from macOS Recovery - Apple Support. Important: Be certain to create a backup of your Mac prior to all of this. That way, you can have something to restore from the Mac from, should anything go wrong with the reinstall. Once reinstalled, try this once more.
