My IT person was finally able to figure out this problem. Apparently it had to do with some incompatibility between (I think) the version of the program installed on the network and the “desktop” version installed on each computer. He said a new version of one had been released but it wasn’t compatible with the existing version of the other. Anyway, he has now fixed it. Nothing to do with registry keys - just required an update of one of the components. Perhaps try looking into this if nothing else is working for you. He said it took several calls to customer service before this issue came to light.