Have them try a repair of avast. Add Remove programs, select ‘avast! Anti-Virus,’ click the Change/Remove button and scroll down to Repair, click next and follow.
It’s literally hitting all of my 200 users - I’m getting dozens of support requests this afternoon. I have to run repair on all 200 users? This sounds more like a corrupt file on one of the Avast update servers, and less like a problem with the Avast install.