iMac won't Boot with various other problems

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Level 1

9 points

iMac won't Boot with various other problems

My iMac has been behaving very erratically the last few days - sluggish, sticking, crashing. I tried to upgrade the OS to 10.13 in the hope that this might fix the problem. Halfway though the installation a message appeared saying that the installation had failed and I needed to restart. Which I tried but it now won't start up. I have had a Kernal panic and the prohibited symbol and every time I try to restart the machine it just gets caught in a loop.

Any suggestions gratefully received.

iMac Line (2012 and Later)

Posted on Apr 17, 2020 8:47 AM

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Answer 1

rkaufmann87

Level 10

141,394 points

Apr 17, 2020 8:53 AM in response to Niche

Please post then entire KP log.

Launch Console.
In the Console app sidebar, select the folder named Library/Logs.
Select the DiagnosticsReporter folder.
Select the most recent crash report to view it.

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Answer 2

rkaufmann87

Level 10

141,394 points

Apr 17, 2020 9:06 AM in response to Niche

Try restarting in Safe Mode per Use safe mode to isolate issues with your Mac - Apple Support

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Answer 3

Niche Author

Level 1

9 points

Apr 17, 2020 9:12 AM in response to rkaufmann87

I have tried that before and nothing happened - but I will try it again.

in the meantime - its just started to show this screen if that means anything? I have turned the mouse on and off again as per the image but nothing changed... thanks for your help by the way...

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Answer 4

rkaufmann87

Level 10

141,394 points

Apr 17, 2020 9:22 AM in response to Niche

It almost certainly is a hardware failure. The most common failures that cause a KP is RAM and a failing HD. I would recommend uninstalling any upgraded RAM (if there was any) and try to boot with the original RAM that shipped with the computer.

If it starts and runs then you have found the problem. iMacs are VERY sensitive to quality RAM and most users on these forums recommend only using Crucial.com or Macsales.com RAM.

As for a failing HD, you can attempt to boot into Recovery Partition (Command + R on startup), open Disk Utility and run First Aid several times on the HD. If ANY errors appear that confirms a failed or failing HD. If no errors appear that doesn't tell you really anything.

I suspect the next stop for this Mac is taking it to your local Apple Authorized Serviced Provider that has the tools to correctly diagnose the computer and then tell you what the problem(s) are. Then you can decide what to do with it.

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