iMac 2010 27" doesn't recognize internal hard disk and doesn't boot

[krknn]

Hi,

I have a 27" 2010 iMac that I'm mostly using as an external display for my newer MacBook Pro. It's been working fine, but suddenly started malfunctioning. The last time it worked I had to force shut down it due to freeze, and didn't think much of that then, as it sometimes does that. However when I turned the computer on next time after a few days, it kept loading for a while and then ended up with a white screen and a blinking folder icon with a question mark in it. I googled and found some possible solutions, none of which unfortunately worked. Sometimes I've also ended up in a white screen with a circular symbol that has a diagonal line through it (the "prohibitory symbol").

Here's what I've tried so far:

• Booting to Recovery Mode (CMD+R on boot). Doesn't go there, instead Apple logo and loading bar shows up, and it keeps loading painfully slowly and then ends up in the screen with blinking folder icon.
• Booting to Safe Mode (shift on boot), doesn't work.
• Tried the boot selection screen and recovery disk (OPT on boot). From here I sometimes can access the MacOS Utilities screen. From there I have tried restoring from a Time Machine backup (have one on external drive). However, after selecting the external drive it asks for the destination drive and in the list there it doesn't show a single hard disk, so I can't select the internal drive, and restoring doesn't work.
• From the Utilities screen I've tried going to Disk Utility to repair the internal drive. Most of the time it doesn't show the whole drive there (just the external Time Machine drive when it's plugged in) so I can't do anything. The one time I saw the internal drive there for some reason, it said "external" which it isn't, and I couldn't access the repair tools as it was grayed out.
• I cannot format the hard drive as it is also grayed out in Disk Utility. Also, can't do it via Safe Mode, as can't get into Safe Mode.
• Resetting PRAM and SMC. No effect.
• Creating a bootable drive with MacOS on it, but that seems impossible, as High Sierra is the latest I can use with the computer and I cannot download that from Apple store or Apple website with my newer machine that runs Catalina. So no luck with that as I can't even make the bootable drive.
• Tried accessing Internet Recovery, but it just always gets stuck in the beginning and doesn't proceed after accepting the terms&conditions.
• Disconnecting all peripherals etc and that didn't have an effect.
• I found some info on accessing Single User Mode and doing a disk check there. I was able to start the mode, but after running some lines of the white text on black background it freezes and I can never get to the point when I could write any commands.

Anything else that might help with the situation? Or ideas on what might be wrong? I was suspecting a physical hard disk failure due to force shutting down, but nothing else comes to my mind. I'm no expert in the area so this is just pure guessing.

(Also one extra thing that I found very weird. Sometimes when I'm trying to boot the Mac, the fuse box of my house (note: house, not anything inside the computer) starts making a buzzing sound. It has never done it before, and the sound stops immediately if I turn off the computer. Doesn't happen with any other appliances in the house. This thing also started happening after the hard disk problems, which seems like a super rare coincidence, as I really cannot imagine how the issues even could be related.)

I would really appreciate any thoughts on this matter. Thank you!

 

[pigoo3]

I was suspecting a physical hard disk failure...

This would be my first guess. With a 10 year old computer...mechanical parts like a hard drive eventually wear out.

Another possibility is a super full hard drive. If it's not super full...then it's probably hard drive failure.

If you happen to have an external HD with a bootable OS on it...this is one way to test that the computer is fine...and then also see if you can do anything with the internal drive.

- Nick

 

[jasongoldworthy]

hi krknn

now the last part is an odd one the iMac itself should be grounded so shouldn't cause any interference on the mains coming in to the house

it could be that your overloading a circuit at that particular moment causing the buzzing to happen,

but again the iMac shouldn't draw enough to cause any fault there,


as for the hard drive seeing as its not showing or letting you run the disk utility could be the hard drive has failed,

another issue here could be the GPU has also failed as this was an issue on the 27" iMac's of the time.