Thanks for this – I tried El Capitan, and got to within a "few seconds" of completing the install before the restart and then – it just hung. Tried several times. So close! Any other ideas? I appreciate your help.
The internal drive was running Lion OS I think. The drive is no longer accessible, so I'm hoping to run everything off the external drive until I can get a new drive installed.
I originally made a clone using CCC of my Macbook Pro (which showed up as a startup disk option in disk utility) but...
Thanks this makes sense – I have a 8GB installer USB thumb drive (with OS High Sierra as I understand that's the limit of the 2011 iMac), and a 1TB WD My Passport drive which I attempted to install on. Unfortunately, I received the following message:
"You may not install to this volume because...
Thanks, I did that, but still only got the basic Disk Utility dialogue box when it restrted from the external HD. I am hoping i can use the external drive instead of an internal drive with access to apps. Looking at using Carbon Copy Cloner
I can start up the Mid-2011 iMac from an external drive loaded with High Sierra OS, but is there a way I can actually use this as a regular drive? All I see when it boots up is Disk Utility etc. Looking for a short-tern fix now until the repair shops reopen and I can get a new internal HD.