Security Update 2020-05 has made my Mac unusable. it won’t finish the boot cycle after 30 minutes (so far).

Thank you. I don’t think I can access the OS that I have on the Mac, as it is not the current version. It’s an older unit, and I’ve been holding out waiting for the new iMac to be released. My Microsoft Office can’t accommodate a newer OS, so my plan was to upgrade all at one time.

Thank you so much for the helpful and straightforward replies. I will probably try to do that, once I get up the nerve. I’m very worried about losing my files, although I did back them up a few weeks ago. I will try to do it again, but the way that this MacBook is performing, I am afraid that it would not work.

The MacBook that I have is old, and I went ahead and purchased a new one. Now, I cannot get the migration assistant to open on my old MacBook to transfer the files. It tells me that it is going to close all apps and log me out, but then it just asks me to log back in. I’m in a bit of a vicious cycle, although I am thinking that this is residue from the problems that were created by that security update. It appears that if I repeat a particular action enough times, it eventually starts performing properly. Last night I tried to airdrop a file to my iPad, and it took an hour and a half to get it to actually work.

If you have any thoughts, that would be wonderful. Thank you so much again for your suggestions.

Unfortunately, I don’t. I’ve ordered a USB to Thunderbolt cable and am hoping that I can do the transfer that way. I just keep running into issues at every turn, all because of that bug-ridden security update. I’m researching the cable transfer on line, because if it requires Migration Assistant, I’m out of luck.

Thanks again for your time!!

Because Migration Assistant isn’t functioning for me. It logs me out, but never brings up any further screens to facilitate a transfer. It just takes me to the login screen, I log in, then open Migration Assistant, and the whole cycle repeats.

I note that this has all been in safe mode, since I have yet to be successful in booting my MacBook normally since the I loaded the security update on Monday night. I’m actually trying a standard boot right now, but 45 minutes in, I’m still on a black screen with a cursor. Going to leave it for another hour, then force a shutdown with the power button until tomorrow.

I will try to follow the procedure in the link you provided once I get the cord, tomorrow. Many thanks for your continued support!

All other suggestions are welcome!