My iMac will not load in operating system

[Bob M.]

I usually shut down my Mac about every two/three weeks or so. Yesterday, when trying to start it up I got an unusual error message : Mac OS is not loading in. And then it opened Mac Installer. I tried a few things and couldn't get it to work at all. I don't really know what to do. I can get my start page to show up at all. I've tried re-starting my iMac a few times with no luck. It's an older iMac but it still satisfies all my minimal computer just fine. I'm running Mac OS iMac High Sierra Mac OS 10.13.6.
Any ideas to get get me up and running again?

 

[MacInWin]

Do you have backups? From your description, the first suspect is that the internal drive has died.

 

[Rod]

Either that or the operating system has become damaged but given the message more likely the drive itself. When the OS is damaged (corrupted) you will see an Apple with a circle and diagonal line across the Apple image.
If the device was operating okay, no other problems, then you might consider installing a new Hard Drive, preferably a solid state (SSD).
Hopefully you have a backup or you data may well be lost.

 

[pm-r]

Any ideas to get get me up and running again?

I'm guessing the previous suggestions by Jake and Rod are valid but have you tried holding down the option key while booting up from a cold boot?

I was just wondering if its PRAM battery has finally died as I am assuming it's an older iMac.



- Patrick
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[Randy B. Singer]

Any ideas to get get me up and running again?

Boot up in Internet Recovery Mode (you, of course, have to have an Internet connection for this to work), go into Disk Utility, and run First Aid. Hopefully that will fix what ails your Mac.

For an Intel-based Mac:
https://support.apple.com/guide/mac-help/use-macos-recovery-on-an-intel-based-mac-mchl338cf9a8/mac
Startup using: Option-Command-R

For a Silicon-based Mac:
https://support.apple.com/guide/mac-help/macos-recovery-a-mac-apple-silicon-mchl82829c17/mac

 

[OliviaClaire]

I usually shut down my Mac about every two/three weeks or so. Yesterday, when trying to start it up I got an unusual error message : Mac OS is not loading in. And then it opened Mac Installer. I tried a few things and couldn't get it to work at all. I don't really know what to do. I can get my start page to show up at all. I've tried re-starting my iMac a few times with no luck. It's an older iMac but it still satisfies all my minimal computer just fine. I'm running Mac OS iMac High Sierra Mac OS 10.13.6.
Any ideas to get get me up and running again?

It sounds like your iMac is encountering a startup issue, possibly related to the operating system or disk problems. One thing you can try is booting into Safe Mode by restarting and holding down the Shift key, which may resolve the problem by performing basic checks and disabling unnecessary system extensions. If that doesn't work, boot into Recovery Mode using Command + R during startup and use Disk Utility to check and repair your startup disk for errors. If the issue persists, consider reinstalling macOS from Recovery Mode, which can sometimes fix software-related problems without affecting your personal files. Additionally, resetting the NVRAM/PRAM by holding Command + Option + P + R during startup might help. If none of these steps work, running hardware diagnostics using Apple Diagnostics or Apple Hardware Test could identify any underlying hardware issues. If the problem persists, contacting Apple Support or visiting an authorized service provider may be necessary for further assistance.