Hi George,

You can just do a web install after you first disable your antivirus software, that will replace the commgr21.dll file.  Then go to your antivirus software and create an exception to not scan the commgr21.dll file (also 2020, and 2019 for me. No other years affected) located in the C:Program Files (x86)/Common Files/Lacerte Shared folder.  Then re-enable your antivirus software and then reboot the computer.  If you just replace the file, most antivirus software will automatically delete or quarantine the file making it unusable.