Your official information source from the .NET Web Development and Tools group at Microsoft.
A Windows Defender and Microsoft Forefront Client Security signature file (1.53.256.0) was released at 8:45 PM (PST) on March 9, 2009 to address a Win32/PossibleHostFileHijack issue. This update modified the hosts file to prevent malicious redirection of websites. As a result, the entry for localhost may have been removed from the hosts file. When this entry is missing and a site is launched in the ASP.NET Web Development Server (aka Cassini) via Visual Studio, Internet Explorer displays “Internet Explorer cannot display the webpage”.
To resolve this issue, open C:\Windows\System32\drivers\etc\hosts and add an entry for localhost:
A new signature file (1.53.288.0) was released at 8:57 PM on March 9, 2009 that does not affect the localhost entry.
More information about this signature file and additional details about the fix can be found at http://www.microsoft.com/security/portal/Entry.aspx?name=SettingsModifier:Win32/PossibleHostsFileHijack&threatid=1758608427027806866 under the “Recovery” tab.
My visual web developer stopped working also yesterday. I made no changes to my system what soever. I'm trying a basic hello world web app and IE just says connection but never connects. I checked the hosts file but its fine. This is frustrating. It was working fine the other day. I have Vista, VSS2008.
I am sorry to hear that you are facing this issue... From your comment it seems like you are using Visual Studio Web Development Server as opposed to IIS... Is that correct?
Can you drop me a line at Vishal.Joshi@Microsoft.com and we can discuss further on what might be going on... In all honesty, we have not heard of any issues outside of the host file one so I too am curious to understand what might be going on...
Please do also confirm whether you are using VWD 2008 express editio or full VS skew...
Thanks for responding to my post. I'll go ahead and also send you an email in addition to this comment. Perhaps this might help someone else. I am using Visual Studio 2008. I'm not using IIS and instead using the asp.net development server. It was working fine until around april 10th. If i debug using firefox it works fine. Firefox quickly resolves my localhost url. If i debug using IE, IE wont connect at all. It just says connecting forever. The URL is
I then replaced the localhost with 127.0.0.1 and it resolved the url. I checked my hosts file and its fine. I'm using windows vista. I'm now checking all my internet settings but they all are set for a wireless connection. I use time warner cable with a linksys router. I also tried disabling windows defender,all anti virus programs and I tried turning off windows firewall. IF you could help me that would be awesome.
You are a life saver, searching for the solution to this problem for nearly a month or so.