I've been running Visual Studio 2005 for about three weeks now and everything has worked just fine. Now all of the sudden I'm getting this error "Unable to connect to Visual Studio's Localhost Web Server"

Any ideas how I can fix it?

Are you on a 64-bit machine? If so, here's how to fix it.  From a command prompt run the following commands

1. cscript %SYSTEMDRIVE%\inetpub\adminscripts\adsutil.vbs set w3svc/AppPools/Enable32bitAppOnWin64 0
2. %windir%\microsoft.net\framework64\v2.0.50727\aspnet_regiis.exe ?i -enable
3. cscript %SYSTEMDRIVE%\inetpub\adminscripts\adsutil.vbs set w3svc/AppPools/Enable32bitAppOnWin64 1
4. %windir%\microsoft.net\framework\v2.0.50727\aspnet_regiis.exe ?i -enable

What this does is switch IIS to 64-bit mode, run the installation of 64-bit ASP.NET, switch back to 32-bit mode and then re-install 32-bit ASP.NET. Doing this causes the right registry keys to be created. This allows Visual Studio to correctly locate the path to WebDev.WebServer.exe so the Visual Studio dev web server can be launched.

Dan,

No, I'm running a 32-bit machine. And just so people know, I have researched this on the forums and found these posts that talk about the same issue, I've tried all of the listed possiblilities and solutions and still haven't fixed the problem:

http://forums.asp.net/thread/1169267.aspx
http://forums.asp.net/thread/1167367.aspx
http://forums.asp.net/1138806/ShowPost.aspx
http://forums.asp.net/1058543/ShowPost.aspx

I also tried executing this command

webdev.webserver.exe /port:8090 /path:"c:\websites\myweb1" /

When I do so I get this error: "The application failed to initialize properly."

I tried to reinstall VS2005 with no success.

Thanks!

Even though you say you have tried "everything" we still need to go down the checklist for more information.

What version of VS 2005 are you running? Beta 2, a CTP, or RTM?

What happens when you Ctrl+F5 instead of F5?

Does this error occur with all new sites, only old file system webs, or both?

What happens when you run webdev.webserver.exe from a command line with no arguments?

Does your Event Log show any application or Framework errors?

Did you uncheck NTLM Authentication in web site properties?

Do you have any firewalls enabled (Windows, Zone Alarm, McAfee)?

My running a 32-bit Windows XP SP2 machine.

What version of VS 2005 are you running? Beta 2, a CTP, or RTM?

RTM

What happens when you Ctrl+F5 instead of F5?

Same

Does this error occur with all new sites, only old file system webs, or both?

All Sites --> New and Old

What happens when you run webdev.webserver.exe from a command line with no arguments?

Same "application failed to initialize" error.

Does your Event Log show any application or Framework errors?

Did you uncheck NTLM Authentication in web site properties?

Yes

Do you have any firewalls enabled (Windows, Zone Alarm, McAfee)?

No

What does your event log say?  (Start-> Programs ->Administration Tools -> Event Viewer)

What has changed on your machine since this used to work?  Are you running under a different user account?  Have you tried running the web when logged on with Admin privileges?  The local webdev.webserver should work both for Normal User and Admins but it's something to check.

"Application failed to initialize" in this case sounds to me like a Framework error.  Can you compile a simple VB app from the command line with VBC.exe, or a C# app with CSC.exe?  That will tell help gauge the health of the Framework. 

Did you install or remove another version of the .NET Framework?  Have you seen any Package Load failures when starting the app?  I'd try launching VS from a command line with the following switches "devenv.exe /resetSkipPkgs /setup" which should force the product to attempt to load any package that may have been ignored earlier, and re-register components with the /setup switch.

hi, madkidd,
i got the same problem yesterday, 
luckily, it was fixed when i got Echo88 's case.

maybe you would find the solution in the post:
http://forums.asp.net/999761/ShowPost.aspx

u stop ur virus protect its   then run ur asp is  working

do one thing go to windows folder--->microsoft.net---->frmaework--> v 2.0 50727---> copy webdev.webserver.exe file

copy this file from someone's machine who has vs 2005 installed, yr file is corrupt.

Hi, I have the same issue, but it seems to go away if I close / restart Visual Studio. It's really annoying. I am running on VMWare though... I usually chalk up oddities to that...