This has not been fixed for me

I have the same issue after an update, it's on Windows 10.
I was not able to save an invoice as PDF.
Version 2021.007.20099 64Bit

The fix that I was given was just a temporary hack. I think the problem is the fact that, for some reason, my default application to read PDF files keeps changing back to Adobe Reader every time I reboot. If I open a file in Reader and do anything with it because I haven't noticed that it isn't in Acrobat then, when I change the default back to Acrobat, the File > Save As issue re-occurs. I have to reapply the fix by going into task manager, selecting the Details tab, and killing the AcrCEF.exe processes again. After that, I can use File > Save As in Acrobat once more.

I'm facing the same problem constantly. Any update has not been help. Only way is to print pdf as a file.
The problem occurs also when you are trying to share the file. Just blank sheet :(

The issue was resolved by through Adobe technical support where they sent me updates to Acrobat Reader and Acrobat Pro. The blank Save As dialog box didn't go away, so we opened the task manager and, on the details tab, we selected AcroCEF.exe. There were actually 5 instances running, but closing one automatically closed them all. We still had Acrobat open while doing this. Thereafter, the File > Save As dialog was populated and I could save the file with a different name in a different directory. It's strange that this process doesn't simply get reset after rebooting the computer. I guess there must be some saved state in Acrobat that restarts the AcroCEF process even after rebooting.
Thanks to the Adobe support staff for helping me with this issue.

Is there a fix for this issue mine is doing the same thing