Late 2015 27” iMac won’t reinstall

[mondoguitar]

I purchased this iMac fully upgraded in 2017. Never had a single issue with it while running Final Cut, Logic, Photoshop, etc. No crashes, no glitches, nothing.

Then after some routine updates a week ago, I clicked “restart”. Upon restarting the computer showed the “question mark folder” icon.

It got to the point where I just formatted the entire internal drive and tried a fresh reinstall of Sierra by default. My time machine backups weren’t showing up when I clicked the restore options. But they are there.

Anyway, what’s happening now is a frustrating cycle of installing installing Sierra, it looks to complete successfully with no errors. Then on the restart, it goes straight back to the internet recovery menu like nothing happened?! I’ve tried reinstalling 4-5x like this and it’s the same every time. About an 8-10min install, reboot, taken back to recovery screen to do it all over again.

I’ve done first-aid on the drive (successful). I’ve unplugged the machine to reset the memory.

It’s now sitting at a repair depot where they’re telling me, “In 10-15 years, they’ve never seen anything like this.” That doesn’t fill me with a lot of confidence.

Does anybody have any insight on what could be the issue here? Installing then going right back to the recovery main menu?

There have been no other issues with this machine EVER. I noises, crashes, restarts, just so random and frustrating.

Thanks in advance.

 

[Cory Cooper]

Hello and welcome.

-What company is the "repair depot"?
-Disk First Aid only finds certain issues - was there a full surface scan run on the drive?
-What storage device is in the iiMac (Retina 4K, 21.5-inch, Late 2015) - 1 TB (5400-rpm SATA), 1 or 2 TB Fusion Drive, or 256 flash storage?
-Did you have any other issues previous to this?
-Does the iMac startup from an external drive with macOS installed on it?

It sounds to me like the drive may have failed.

C

 

[mondoguitar]

- A local computer shop is the authorized place. Was either that or London Drugs.
- It’s a 27” late 2015 with 1GB SSD
- No other issues ever, while running the machine. Final Cut, Logic, Photoshop, had them all open at the same time many times and never ever a hiccup.
Only problem has been after installing software updates and being prompted for a restart. Then after that restart, the computer can’t find the hard drive.
- Installing to an external drive did the same thing. It started to install Sierra, looked successful, but on the reboot, went right back to the recovery menu.

They’ve had it over a week. Run all the diagnostics. In consultation with Apple, they said they’ve ruled out everything and it has to be the Logic board. So now waiting for that to arrive any day.

They also replaced the RAM, didn’t solve the reboot issue.

 

[Cory Cooper]

OK, thanks.

Yes, sounds like it could be the logic board.

Keep us in the loop and good luck!

C