Hi Bob Howard,
Thank you for your prompt response.
Most likely, the problem is caused by local security permissions as you suggested. We were not able to reproduce the issue and we don't think it has to do with Sitefinity.
What we would suggest in this situation is check the user’s permissions and local access. You can check if you can access the desktop from the Files > Upload a file screen.
Also, you can create a page in a non-Sitefinity project, insert a Browse button and check if you can access your desktop from other applications.
the Telerik team