>I've run into this the other day. Worse Visual Studio kept resetting the flag after I reset manually it in the project file.

Exactly what I first tried.

>The way to fix it is to set the UseIISExpress flag to false in the project file. At that point the project should open at least. You'll have to reset the Web preferences.

In your first line, it says that the flag is reseted automatically, even after you changed it. Then, in this point, you mention to do the same. I am not sure if you wanted to say something different. I am a little bit confused. In my case, this is also what I tried at first. I went in the project file, the .vbproj, and removed the UseIISExpress XML tag. It was already set to False. That did not change anything. When entering the VS environment, VS will put that XML tag back in the .vbproj file and set it to False. Thus, this results in the same.

It seems another reset is necessary somewhere else.

>You should make sure to uncheck the Apply server settings to all Users checkbox - this syncs the settings across everybody who opens the project. Unchecked means your local settings are stored in the solution .SUO file which is local to you and not shared. This way everybody can have their own settings. After you change anything in this section, make sure you explicitly save your project and solution (Save All from File Menu).

That's good to know.