Somehow I wound up with pro installation after I rolled back my computer… Ref: http://forum.avast.com/index.php?topic=116525.msg906717#msg906717
If I do upgrade, is avast still going to stop my CAD programs from working? They are working now but once your new version was installed they stopped.
The same thing happened to me when I had to do a system restore back in time a few days. I got switched to a trial version of the pay one. Can’t be a coincidence.
This really should be in a separate topic.
To roll back to the free version just…
That is one question that is impossible to answer as we don’t know what else you have on your machine.
Which CAD software are you using? You can always try to run v8.0.1483. You might need to make exclusions for your
CAD program in both the File and Behavior Shields. 
I do not have the option to go back to Avast free. Here is my screen shot.