I use an extreme pro 256 as my boot volume for an iMac late 2015. I am currently running Catalina from it. I upgraded the internal hard drive to Big Sur successfully. But when I try to install Big Sur on the extreme pro, the install does not complete. On final restart, the install gets stuck with an apple logo and a progress bar at about 40%. I left it like that for hours, I tried multiple restarts, but I could not get it to work. I have another external hard drive from which I was able to downgrade back to Catalina successfully.
Has anyone been able to install Big Sur on the Extreme Pro SSD 256 and run your Mac from it? Any tips to get it to work?
