I've seen this one too. It's a brain bender. It's probably associated with some problem on the client side. I've had some computers produce this problem while others didn't, and with no apparent reason. Here are some things to try:

1. The file size may be too large and the session is timing out. You can try to up the session timeout in IIS.
2. Make sure there are no "&" in any of the file names
3....

Various Issues with WebDAV on Windows and Mutliple Solutions

After over 7 years of WebDAV experience with Windows I found the following solutions to a the most common WebDAV of issues.

Issue 1.

If you receive any type of error message trying to transfer files to WebDAV. Try the following:

Make sure WebDAV is patched. Windows 2K3 and prior have at least one patch. The biggest problem with...