I did all updates, including Big Sur 11.4. This let me install MacOS Mojave (10.14). Booted in internet Recovery Mode (Option-command-R). MacOS Big Sur 11.4 caused my iMac 21.5' 4K (2017) to crash repeatedly MacOS Big Sur 11.4 caused my iMac 21.5' 4K (2017) to crash repeatedly (i.e., hang on mouse click indefinitely, totally unresponsive interface). My Mac Book Pro dates from 2019 and Big Sur OS update just messed it all up for over 3-4 weeks now. I must say I'm quite disappointed with MAC on this Big Sur upgradr. So I will go get my MAC diagnosed asap now to see what's wrong. Latest discussion with MAC support went like ' we cannot help you downgrade MAC OS back to Catalina' but only re-install Big Sur (The culprit.). This being said, next thing my MAC would no longer start and when trying to start up from macOS Recovery, my MAC would not display a message error -1008F. Something likely did not go well for no option was there for me to re-install Catalina but just Big Sur which I do no want any longer. I followed up their step-by step guidance for macOS Recovery on Intel-based Mac computers. I could no longer use Big Sur to the risk of overheating my MAC with potentially damaging it for good so decided to contact Mac Support to uninstall Big Sur and re-install Catalina which was working just fine.

Like many of you I upgraded a few weeks back from Catalina to Big Sur confident that there would be no issue. It's not my new thread on the issue but could not find my last post so decided to create a new one. He has reinstalled os Catalina hence me being able to email this today.ĭoes anyone have thoughts about what i can do from here as I would like to bring my iMac up to date but I do NOT want to go through this again and its already cost me a lot of money to be able to use my machine again.īig Sur upgrade and now Big issues Hi Apple Community,

He managed to recover all of my data onto an external 2Tb Toshiba drive (thank goodness) BUT he tried to reinstall Big Sur with no luck either. On Monday, I took my iMac to a repairer who did an excellent job in updating my iMac with a Samsung 2Tb SSD drive and maxed out my RAM. The bottom line is that having spent around 10 hours trying to reinstall big sur I kept getting the message 'application denied'. I contact 4 apple support people who were helpful, we went through diagnostics, recovery etc etc. I tried over and over again to reboot with no luck. On rebooting it progressed to around 50% and stopped. Last Saturday my 2017 iMac 4k retina, crashed using the lasted Big Sur update. Can anyone offer help and guidance please?

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