David, I'm having this same problem at a 2014 client. It has to do with the workfile not being able to be initialized. It has something to do at the workstation level. I've tried to get resolved with Sage in the past and they cannot help. Try previewing something else from that workstation, like the GL Trial Balance. Then close out of the preview and close out of the task. Then check the company GL directory and I bet the workfile did not delete. Normally temporary workfiles delete after you exit out of preview, or after the report is printed if you chose to directly print. I was just working on this issue yesterday with my client's IT guy. They have this problem ONLY when running Sage at the Sage server (which I do when I'm helping them remotely). I've been trying to get customers renumbered in a test company where nobody is in but me, and I get an Error 0 that the file is in use - which I had a MD programmer look at the code yesterday and he determined it was the workfile that it could not clear. As soon as I tried this renumber task from another workstation at the client (I'm on site), the renumber worked just fine.