Hi Khurram,

This is the by design behavior. I have replied a similar issue before. The workaround is setting the same port for each project. For more information about this issue, please refer to my reply in the following thread. Thanks.

Debugging website in a solution with many websites starts many web server instances
http://forums.asp.net/t/1098901.aspx

Thanks for the reply and clarification that "its not a bug but a feature" :)

When I specify the same port in different web application projects; and debug the solution with a specified startup project; I get the following errors..(I tried even specifying different virtual paths but with same port).....though a single instance of webdev.webserver runs: its even more annoying!

WebDev.WebServer.exe has stopped working
Description: Stopped working
Problem signature:
Problem Event Name: CLR20r3
Problem Signature 01: webdev.webserver.exe
Problem Signature 02: 9.0.0.0
Problem Signature 03: 4731664b
Problem Signature 04: System
Problem Signature 05: 2.0.0.0
Problem Signature 06: 471ebf0d
Problem Signature 07: 2c04
Problem Signature 08: 40
Problem Signature 09: System.Net.Sockets.Socket
OS Version: 6.0.6000.2.0.0.256.1
Locale ID: 1033

My solution has a winforms app and few web application projects. The winforms app is the startup project for debugging. The first time, debugger works fine; break points get hit. But when I stop debugging; change some code and re-debug (hitting F5) Visual Studio reports "Error while trying to run project: Unable to start debugging." I have to manually shutdown the webdev.webserver before second debugging session. The solution and projects are migrated from Visual Studio 2005. The target framework for all the projects are .NET 3.5. I have tried creating a new solution with multiple web application projects and a winforms project; its debugging expereince is fine...though the above "webdev.webserver has stopped working" issue with single ports on all web app projects is still there....

Hi Khurram,

Thanks for your feedback. For this secnario, I recommend you using IIS as the web server, then you will not encounter this issue. About how to change existing web projects to use IIS as web server, please refer to my reply in the following thread:

do I need to publish my website to be able to access it via server name?
http://forums.asp.net/t/1168282.aspx

I removed all the webprojects from the solution, saved the solution and then re-added the web projects. The debugging expereince (Unable to start debugging on subsequent F5s) is normal now. Running webdev.webserver for all web projects I guess is not that big issue any more; I think we can live with it till we re-organize our solutions merging these different web projects.