RMC worked up until recently. Now, I get an Unexpected Fatal Error when I run it......

Unable to generate a temporary class
(result=1)
error CS0016: Could not write to output
file
'c:\Users\Michael\AppData\Local\Temp\
kxh7bxde.dll' -- 'Access is denied.'

I have uninstalled/reinstalled, rebooted many times, turned off virus checker/firewall. I even tried installing the current demo version from the site, to no avail.

What's wrong?

Help, and thx in advance!