Did you ever find a permanent solution? We wiped and reinstalled the OS and applications on a workstation having this issue and that fixed it for us, but I was hoping an easier fix was found. This issue started when we moved our PCs and users on to a windows domain. It is obviously an issue with user profiles or the way DMS uses the TEMP space.

We have tried reinstalling Office and DMS without success in fixing this issue. The TEMP system variables are intact and excel itself does not have issues opening multiple files.