Visual Studio is asking to create virtual directories in IIS when I open a solution. Could this be because projects within the solution have been configured to use IIS rather than Cassini?
The dialog message is:
"The local URI ... specified for Web project ... has not been configured. In order to open this project the virtual directory needs to be configured. Would you like to create the virtual directory now?"
Yes it is. If a web project is configured to use IIS (on the Web tab in the project properties -> "Use local IIS web server"), Visual Studio requires that the path defined exists in IIS as a virtual directory and corresponds to the project's location on disk. If the path does not exist in IIS, Visual Studio will offer to create it for you.
来源：https://stackoverflow.com/questions/3093433/visual-studio-creating-iis-virtual-directories-when-solution-opened