Please help an Octogenarian with serious problems after High Sierra Upgrade!

[SonofJake]

Hi, I'm posting on behalf of my father; he's over eighty and has been an enthusiastic Mac user for many years but has hit serious issues after upgrading to High Sierra OS on his iMac (now 8 years old). Initially he just got a blue broken display (image file attached )with Apple symbol in the centre and a progress bar that half completed and stopped; he rang Apple help line who just told him his machine was obsolete and nothing could be done to fix the problem ("thanks, guys!"). I looked up some advice on-line and we tried re-stting the NVRAM and SMC, which we appeared to do, but the machine then just moved to a grey screen with similar apple logo and progress bar (image file attached). He has had Time Machine running a back-up on a separate 1TB drive, which he's disconnected for the moment. Any advice or recommendations of good technical support in the Birmingham UK area would be gratefully received. Dad's stuck in his retirement flat most of the time, so he really misses being able to use his iMac and having to make do with his iPad Air (...like I said, he's a great Mac enthusiast!). Many thanks in advance for any help.

 

[honestone]

This link shows which Macs can run High Sierra:

https://macpaw.com/how-to/will-my-mac-run-macos-high-sierra

For an iMac, it needs to be at least a "Late 2009" model. Given it is late 2017, that means only iMacs which are at least "Late 2009" models. You stated that your father's one is 8 years old, so not sure how much of a "Late 2009" model he has.

Here is one possible way for you to help him out (thank god he has been backing up with Time Machine). What exact Mac model do you have, and what exact iMac model does he have? If your model has either a Thunderbolt or Firewire 800 port, and his has a Firewire 800 port (I suspect his does), then you can boot his Mac (after connecting to your Mac via the "appropriate" cable) in Target Disk Mode. This link explains Target Disk Mode:

http://osxdaily.com/2010/04/07/how-to-boot-a-mac-in-target-disk-mode/

Assuming you have the file "install macOS Sierra" on your machine, you can then get his iMac back to Sierra, along with all the needed "stuff" from his external drive that contains his Time Machine backups.

 

[Spawn_Dooley]

This screen issue, you wrote it's related to an upgrade to High Sierra. Did the Mac perform "normally" at any stage after the upgrade? Is the TimeMachine backup a High Sierra backup?

If the backups were Sierra 10.12.x then I was going to suggest booting up holding down the Option key with the TimeMachine drive connected, & restoring from the last stable backup.

Probably need more info from you first.