We are in the middle of a project where Fiddler makes our work easier with monitoring internet traffic between our web service and Microsoft Word.
Firstly, we set up our Sense/Net portal to use windows authentication to work with WebDAV and also associated the computer’s host name with the site because this is the only way for Fiddler to be able to monitor local traffic between our webservice and Word. There seemed to be a configuration problem in some computers when trying to open files associated to Word right from Sense/Net because the Windows Authentication Dialog popped up three times asking for credentials. On other computers it worked without asking for any username and password.
We spent hours trying to figure out what could possibly cause such an unwanted behavior but with no luck until we realized that when Fiddler wasn’t running, there was no problem. So we dug ourselves into Fiddler’s configuration and we found the following option “Act as system proxy on startup”. By turning off this guy made us the happiest people on the Earth, the issue described above disappeared like a grey donkey in the fog.
You can find this option under Tools \ Fiddler options… \ Connections.
Note that, turning off “Reuse client connections” and “Reuse connections to servers” may also help in same other cases.