Mac OS won't start outside of Safe Mode

[ks-man]

I tried upgrading my iMac to Big Sur and it now won't start outside of Safe Mode. During the startup progress bar it goes about 25% of the way and then the screen flashes black and it then comes back to the prgress bar showing 10% and just sits there. If I try Safe Mode it then loads up fine. I don't have any peripherals. I tried First Aid yesterday and somehow the hard drive got wiped (great...).

In Safe Mode I was able to set up all the initial preferences for the OS but again it freezes outside of Safe Mode. I just tried erasing the hard drive intentionally and am reinstalling Big Sur. I'm not optimistic.

What would the black flash during startup indicate? Apple Care has expired so I"m trying to avoid calling Apple if I can fix it myself. It is a mid 2017 iMac with a 2.3Ghz Dual Core Intel i5. Thanks!

 

[appltech]

Hi! Was the problem fixed after reinstaling Big Sur? According to your description, the problem might be with kernel (1 of 4 system initializations steps) that shows the progress bar and may be fix by reinstalling the system, though it depends

 

[ewu]

if you are using fusion driver, it may be because installation didn't finish and that progress bar means installation continue.

I remember It takes almost one whole day for me to finish upgrading in fusion driver