ASP.NET fixes page

This page is no longer being updated. Please see this page instead.

[last update - 20th November 2007 - added 938276 and .NET 2.0 SP1 entry,]
[previous update - 31st August 2007 - added 939866,]
[previous update - 3rd August 2007 - corrected some of the versions for current beta products]

There is nothing worse than wrestling with a problem for ages only to discover later that there is already a fix for it. I therefore felt it would be useful to summarise what fixes have been done for ASP.NET 2.0 since it was released. Here are a few important points before we go any further:

  • What is a hotfix? Make sure you can answer this question before you go ahead and start downloading or installing fixes. A good description can be found on the DevDiv Hotifx Public Availability Pilot Program web site.
  • When we ship a fix we always try to minimise the number of files affected. So far, most ASP.NET 2.0 fixes we've released only affect three files: System.web.dll, WebEngine.dll and aspnet_wp.exe. The fixes listed in the first table below all update those files to the version number indicated.
  • Fixes are cumulative. So for example if you install the fix that says it installs version .832 then you are also getting the bug fix that is described in the article that says it installs version .819, .804 etc., etc. That's why I've written the below table in reverse version number order.
  • Check the version number of these files on your system first. If your version number is already higher than the version number indicated in the article then it means you already have that bug fix. If you are getting a problem that sounds like what is described in the article but you already have that fix, then you are probably getting a similar problem or set of symptoms due to some different underlying root cause.
  • At the time of writing, the simplest way to get all the latest, current ASP.NET 2.0 fixes is to go to Microsoft Update and let it scan your system and get all recommended critical updates. This will include MS07-040 which updates significant chunks of the Microsoft .NET Framework 2.0, including ASPNET 2.0.
  • If for some reason you don't want that security update but want a more targetted hotfix package for ASP.NET only then the next simplest thing would be to go to the connect site and directly download one of the fix packages for ASP.NET that are available there that includes the fix you are looking for (see below).
  • If you are still not sure what fix you need, are having trouble getting hold of a particular fix, are having trouble installing it or have installed it but it hasn't solved your problem then contact Microsoft Product Support.  Scott Guthrie has already blogged about one of the recent fixes listed below and has an excellent introduction to how to contact support (see "Contacting Microsoft Product Support" on that blog entry).
  • If you are having a specific problem obtaining or installing a fix or with solving some ASP.NET issue please don't contact me directly. Unfortunately I cannot scale up to be a one man support organisation. Please utilise our global support organisation as described above.


Fixes that affect the three core ASP.NET 2.0 files of System.Web.dll, WebEngine.dll and aspnet_wp.exe (located in WindowsMicrosoft.NETFrameworkv2.0.50727)

Version Comment Description
2.0.50727.1433   Microsoft .NET Framework 2.0 SP1 (included with .NET Framework 3.5)
2.0.50727.1378 Beta This is not a released hotfix, however Microsoft .NET Framework 3.5 Beta 2 does update the core .NET 2.0 Framework files including the ASP.NET 2.0 files and therefore includes all the below listed hotfixes. So this may be of interest if you are working with the Orcas betas.
2.0.50727.1373 Beta Windows Server 2008 June CTP
2.0.50727.1320 Beta Windows Server 2008 Beta 3
2.0.50727.1318 Beta Microsoft .NET Framework 3.5 Beta 1
2.0.50727.945   FIX: Error message when you try to run an ASP.NET 2.0 Web application if you do not associate the My_Computer_Zone code group with the "full trust" permission set: "Server Application Unavailable"
2.0.50727.926   FIX: Error message when you run an ASP.NET 2.0 Web application that is built on the .NET Framework 2.0: "The constructor to deserialize an object of type '<custom object>' was not found"
2.0.50727.924   FIX: Error message when you run an ASP.NET 2.0 Web application that is built on the .NET Framework 2.0 after you install the MS07-040 security update: "Type 'System.Web.HttpHeaderCollection' is not marked as serializable"
2.0.50727.924   FIX: The # Induced GC performance counter value increases quickly and CPU usage becomes high when you run an ASP.NET 2.0 Web application that is built on the .NET Framework 2.0
2.0.50727.912   FIX: A RemotingException exception occurs when you compile a large Web site project that is built on the .NET Framework 2.0 by using the ASP.NET Compilation tool
2.0.50727.900   FIX: Blocking problems may occur when you use SQL Server to store ASP.NET session state information for a Web site that experiences high loads
2.0.50727.832   MS07-040: Vulnerabilities in the .NET Framework could allow remote code execution Although this security update patches the core ASP.NET 2.0 files and therefore includes all the below fixes, it also patches many other files in the .NET 2.0 Framework. Please read the above article before proceeding.
2.0.50727.819 ScottGu blog Download on Connect FIX: You may receive an exception when you browse a .NET Framework 2.0 ASP.NET Web application
2.0.50727.819 I wrote this article :-) FIX: Error message if you modify a resource file when an ASP.NET 2.0 application is running: "System.InvalidOperationException The resource class for this page was not found"
2.0.50727.804   FIX: Error message when you try to visit an ASP.NET 2.0-based Web page: "HttpException (0x80004005): '/HandlerTest/WebForm1.aspx/a:b' is not a valid virtual path"
2.0.50727.802   FIX: A Web application that is built by using ASP.NET 2.0 does not use the attribute value that you set in the xhtmlConformance element
2.0.50727.312   Windows Vista RTM Release includes this version
2.0.50727.244   FIX: An InvalidViewState exception is not thrown as expected when you use the Triple DES encryption type to validate the System.Web.UI.Control.ViewState property in the .NET Framework 2.0
2.0.50727.219   FIX: You may receive an "InvalidCastException" error message when you try to debug the dump files for Windows SharePoint Services
2.0.50727.213   FIX: The data in a POST request is truncated to 49,152 bytes when an ASP.NET-connected application receives the POST request
2.0.50727.210 Contained in MS06-056 I wrote this article :-) FIX: Some characters in a text resource may not appear correctly when you try to embed the text resource in a Web application that is built on the .NET Framework 2.0
2.0.50727.174   FIX: Error message when you try to run an ASP.NET 2.0 Web application that includes Web services: "The file <FilePath> does not exist"
2.0.50727.166   FIX: You may experience an unexpected AppDomain restart in an ASP.NET Web application that is based on the .NET Framework 2.0
2.0.50727.103   FIX: The Click event for the associated Button control is not raised when page validation fails in a Web application that was built by using ASP.NET 2.0

FIX: You receive a ThreadAbortException exception in an ASP.NET Web application that is based in the .NET Framework 2.0 when the Async page directive property is set to true

2.0.50727.80 Download on Connect

FIX: You may receive an InvalidCastException error in an ASP.NET-connected Web application

2.0.50727.62 Download on Connect FIX: You receive an exception error message when you specify a Content-Length HTTP header that is larger than 2 GB in ASP.NET 2.0
2.0.50727.62   FIX: Error message when you try to run a Web application that was built by using the .NET Framework 2.0: "Overwhelming changes have occurred"
2.0.50727.62   FIX: Error message when you try to go to an ASP.NET page by using a URL that contains Unicode characters: "HTTP error 400 'bad request'"
2.0.50727.62   FIX: ASP.NET 2.0-connected applications on a Web site may appear to stop responding
2.0.50727.56   FIX: Error message when you try to browse the root folder of a Web application that is built on the .NET Framework 2.0: "Object reference not set to an instance of an object"


Other fixes outside of the main set of three files:

2.0.50727.803 System.Web.Mobile.dll FIX: You may experience a decrease in the performance of a .NET Framework 2.0-based application when you call the System.Web.UI.MobileControls.Style.GetValue method many times
2.0.50727.92 AspNetMMCExt.dll FIX: IntelliSense does not work when you use the MMC Snap-In for ASP.NET or the Web Site Administration Tool to add an existing Web.config file to a .NET Framework 2.0 ASP.NET Web site


Hope this helps!


[Updated 8th April 2009. I don’t generally like to change posts after they have been published but I wrote this post while some of the KB articles were still being authored. For a number of reasons there have been some changes to which articles document what issue, so I’m updating the below table to reflect the current situation as accurately as possible]

[Updated 27th April 2009. Correcting some build numbers and adding rollup KB969612]

There have been a few ASP.NET issues lately that have had to be resolved by the production of new hotfixes.

These fixes are recent and are not included in either the Microsoft .NET Framework 3.5 SP1 nor the subsequent .NET Framework Family Update.

When we release a number of fixes at around the same time, it can get a little bit confusing as to which fix package you actually need to get hold of and install in order to resolve the problem you are having. In due course this should be clearly documented in the KB article.

The below tables will hopefully help clarify things a bit. The first column has the link to the KB article that documents the issue. The description column is the high level description of the problem. You then have to decide which operating system you need the fix for. The fix packaging technology is different for different families of operating system. Look in the column appropriate to what you need and look down to the correct row. Either click on the link you find there or, if you see a ‘V’ continue looking down until you find a link or information about how to get the fix.

An important point is the build number. Microsoft hotfixes are always cumulative. So if a fix is included with a particular build of a particular set of files then any later build (higher build number) of the same files will include all previous fixes that affect those files.

Note: at the time of writing this blog post, not all the KB articles describing the problems have been published. So the KB article link may not yet work when you read this. The fixes are available however.

The fix packages in the first table update this set of files:


I think of these as the “core” ASP.NET files.

The file version number is 2.0.50727.xxxx where xxxx is the build number.


KB describing the problem Description Fix package for Windows 2000/XP/2003 Fix package for Windows Vista SP1 / Windows Server 2008 Build number
KB961847 FIX: Error message when you view a page in design mode after you recompile a .NET Framework 3.5 Service Pack 1-based project: "Error creating control – 'ControlInstanceName [text]' could not be set on property 'PropertyName'"



KB961864 FIX: Web clients may have several problems when you access an ASP.NET 2.0 AJAX-enabled Web site



KB961884 FIX: You experience very slow performance on an initial request to an ASP.NET Web site after you change the App_Code folder, the bin folder, or the Global.asax file





FIX: ASP.NET Dynamic menus do not render correctly in IE8 in non-compatibility view



KB961902 FIX: Error message when you compile an ASP.NET project that contains many application resource files: "A first chance exception of type 'System.ArgumentException' occurred in mscorlib.dll"



KB967535 FIX: A hotfix is available to fix two problems in ASP.NET on IIS 7.0 for Windows Vista and Windows Server 2008 n/a


KB969612 Description of the hotfix rollup package for ASP.NET 2.0: April 2009 KB969612   4028



The following fix affects this file:



KB describing the problem Description Fix package for Windows 2000/XP/2003 Fix package for Windows Vista SP1 / Windows Server 2008 Build number
KB957661 FIX: Exception error message when you use a virtual path provider to serve a Web page that has a ScriptManager control: "Directory '<file directory>' does not exist. Failed to start monitoring file changes." KB957661 KB957661 4030