One user?  Format C:, or give them a new PC, it's corrupted.

Yes it is just happening for one user and her workstation acts as the server. Her workstation crashed recently and their IT got a new power source for the pc, since that they have been receiving the error message :"can't create control......."

An unistall/reinstall or a repair and running the regacc again solves the problem but it is not cost effective for the client who has to call everyday.

Thought perhaps it was the Avast anti-virus sweeping some files, which has happened to other clients before who also have the anti-virus and Sage 300 installed.

Your suggestion would be a new workstation instead?

That's what I said.

I realize what you said in the post Jay, I was just giving some more information especially about the Anti-virus.

None of my clients use Avast because I insist they don't, it's well known for false positives.