Yep, I also cannot export my settings but only on one of my machines, the other one works fine. Both are Win 10 x64; however, there are a few subtle differences as described below:
desktop, win 10 x64, upgraded to 12.1.2272 from a previous version, import settings works ok, export settings works ok
laptop, win 10 x64, clean install of 12.1.2272 (never had avast installed before), import settings works ok, export settings does not work ok (getting access denied).
Just for the record, I did try the safe mode, aswclear, and a complete reinstall (laptop) to no avail.
gus