Prevent iMac's dead HDD from being detected

[Hexley]

I have a late 2012 27-inch iMac (Slim unibody iMac without Retina Display) that was BTO'd with a 1TB Fusion Drive.

1TB HDD died within the last 12 months so I have been running on the 128GB Blade SSD SATA

Whenever I boot up macOS detects the dead drive and either tries to start it or freezes it thus slowing down boot up or needing me to do a forced shut down and cold boot.

Is there a way for me to tell macOS to ignore the dead drive and just stick to the 128GB Blade SSD SATA?

 

[Fishrrman]

Try this at startup (may help, may NOT help, but try anyway):

Proceed like this:
1. Press power-on button
2. IMMEDIATELY hold down the option key and keep holding it until the startup manager appears
3. You should see the SSD in the list of bootable devices.
4. Select SSD with pointer, then hit return.
Does this make any difference in how it boots up?

A quick and easy thing to try.
Let us know if it changes anything.

 

[Zeke D]

I would suggest booting to an installer, and once you get to the install screen, click cancel, then select boot disk. Select your SSD, then EFI should seek that drive first.

 

[xgman]

I had the same problem with an older 2012 imac my son has, and in fiddling with the fusion drive and trying to format the 2 parts of it to reinstall the OS, even as the HDD was noticeably failing, I ended up removing any trace of the HDD which never came back in the process of reformatting and erasing it. When I had to CMD R to internet recovery, I was surprised to see the it installed High Sierra, and forced auto format the remaining 120SSD to APFS and now is working normally with absolutely no sign whatsoever of the old HDD part of the Fusion. I don't really remember all the steps, but I think my HDD just ended up failing. Only problem now is SSD is kinda small unless I stick a usb 3 ssd on the back of the imac.

basically I did the erase/HFS formatting with disk utility in the Recovery Environment. After that at some point on reboot there was no OS and the Internet Recovery just started by itself.