Aaron Stebner's WebLog

Thoughts about setup and deployment issues, WiX, XNA, the .NET Framework and Visual Studio

Removal tool to fix .NET Framework install failures

Removal tool to fix .NET Framework install failures

Rate This

I wrote an application late last year that is designed to clean up computers that have problems getting the .NET Framework 1.0 or 1.1 to install correctly.  I have been working on refining the tool for the past couple of months, working out some bugs, adding additional cleanup features, etc.  The .NET Framework setup Product Support team has been using this cleanup tool for the past few months to help resolve many cases, and the internal Microsoft helpdesk has also started using it to solve internal cases where employees cannot get .NET Framework service packs or hotfixes to install correctly.  I have also been sending this tool out to individuals who email me via my blog and ask for help resolving setup problems - most commonly this is because of issues installing .NET Framework service packs or hotfixes such as MS05-004.

Since I have been seeing really good success rates for using this cleanup tool and it has proven to speed up the process of resolving issues so customers can get the .NET Framework installed correctly and start using managed code on their computers, I decided to try to get a KB article written up with a copy of the tool that customers could download on their own without needing to contact me directly or call our PSS team.  The KB publishing process can sometimes take a while with technical reviews and things like that, so in the meantime I am going to post a link to the tool here on my blog.

You can download the tool by visiting the .NET Framework Cleanup Tool User's Guide and using one of the download links listed there.

There are a couple of very important caveats that you should read before using this tool to cleanup .NET Framework bits on your machine:

  1. You should try to perform a standard uninstall first.  This tool is not designed as a replacement for uninstall, but rather as a last resort for cases where uninstall or repair did not succeed for unusual reasons.
  2. This cleanup tool will delete shared files and registry keys used by other versions of the .NET Framework.  So if you use it, be prepared to repair or reinstall any other versions of the .NET Framework that are on your computer to get them to work correctly afterwards

The tool itself has been fairly well tested, but I'm sure it is still not perfect.  I'm still in the process of fixing bugs as I find them and adding features to make it more effective at cleaning up known issues and to make it more intelligent about identifying root causes so we can fix the underlying bugs in .NET Framework setup for future releases.  As I update it, I will post updates to my blogs and update the copy of the tool located at the link above.

I hope this tool will be helpful in resolving problems installing the .NET Framework.  Please let me know if you run into any issues while using the cleanup tool or if you are still unable to install the .NET Framework (or any service packs or hotfixes) after running it.

<update date="3/3/2009"> Added a link to the .NET Framework Cleanup Tool User's Guide, which contains the most up-to-date download location for this tool. <update>


  • I was receiving an error installing the 2.0 Framework with an 'Access Denied' error on the file Microsoft.VisualBasic.vsa.dll and I thought I would post the solution I found as other people have been encountering it.

    By using FileMon, I could see that the ACCESS DENIED error was actually being return when the setup tried to create the file GACLock.dat in the folder c:\winnt\assembly

    For some reason, Administrators had lost permission to write to this folder.

    I was not able to apply permissions using Windows Explorer, but could set Administrators to having full control in this folder by using the following CALCS command from the command line:

    calcs c:\winnt\assembly /E /P BUILTIN\Administrators:F

    After this the framework installed OK.
  • Hi,

    I'm using Windows XP x64. I am trying to uninstall Microsoft .NET framework x64 BETA 2 (Shipped with VS 2005 BETA). The framework seems to have had installed a couple of important files in 'Program Files (x86)' which contains, due the uninstaller, 'illegal characters' (the parantheses?). Because of this issue I can't uninstall Microsoft .NET framework x64, which I have to do in order to be able to install VC++ Express Edition.

    The only error message I get is:
    'Error 1324.The folder path 'Program Files' contains an invalid character.'.

    Is it possible to change the registry keys somewhere from 'Program Files (x86)' to perhaps 'Progr~2'? Or is there another method?
  • Hi Zan - I don't think the parentheses is an invalid character since Windows allows you to create a folder with that name. Can you please try the steps listed at http://blogs.msdn.com/astebner/archive/2005/10/30/487096.aspx to try to manually remove the .NET Framework 2.0 beta that you have on your system? Hopefully that will get you past this error.

  • I just wanted to say thanx for this excellent tool.

    I had apparently insoluble problems with .Net 1.1, and you tool fixed it immediately.

    Thanx very much,

    James Muir
  • Not even Liquid Hot Magma could solve a corrupt .Net install. That is, until your program saved the world, or at least small portion of it. THANK YOU!
  • Work fine... thank you very much...
  • I get the error message "Error 25015.Failed to install assembly ... Vsa.dll' because of system error: Data error (cyclic redundancy check).  

    what can i do ..
    i am running windows XP media center and SP2

    i need helpplis...

    you can send me an email to nx_2020@hotmail.com coz its urgent
  • Hi Gody - can you please try to use the manual removal steps for the .NET Framework 2.0 that are listed at http://blogs.msdn.com/astebner/archive/2005/04/16/408856.aspx and then try to re-install the .NET Framework 2.0 and see if that resolves this issue?  If that doesn't help, I would suggest contacting Microsoft technical support (you are entitled to a free support call for .NET Framework setup issues).  I'm sorry I'm not able to be more helpful here.
  • Thank You. Saved me a complete reinstallation!!!
  • Hi Aaron,

    Wanted to thank you.  We couldn't get .NET 1.1 off the machine and kept getting this silly dialog.  Your tool worked like a charm.


    C# Corner
  • Hi,

    I also have the error Failed to install assembly...Vsa.dll The Device is not Ready.

    I've tried setting the security settings as Derek suggests, and running FileMon doesn't return an error.

    From dd_netfx20:
    03/11/06 10:27:29 DDSet_Error: Failed to install assembly C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Microsoft.VisualBasic.Vsa.dll. IAssemblyCache->InstallAssembly() returned -2147024875.
    03/11/06 10:27:29 DDSet_Error: Failed to install assembly 'C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Microsoft.VisualBasic.Vsa.dll' because of system error: The device is not ready.

    FileMon notes End Of File on VisualBasic.Vsa.dll but no failures.

    Can anybody suggest anything else to help?

  • Guys,

    I've solved this problem. I had to remove all my framework versions and then in my Windows/Assembly directory I had some existing subdirectories that needed clearing out, including GAC_32 and GAC_MSIL.

    I'm not sure what happened along the way to cause this problem, as I had hoped to run different framework versions alongside each other. But thanks to Aaron, using your manual uninstall process got everything working again.

  • Hi AndyC - I'm glad to hear you got this issue resolved.  In case any other folks read these comments, the manual steps Andy is referring to are located at http://blogs.msdn.com/astebner/archive/2005/04/16/408856.aspx.
  • Hi,

    We have one PC that gets the following error in the Microsoft CRM 3.0 Outlook Client installer, and can't get past the system requirements phase of the installation:

    "Microsoft CRM Client for Outlook Setup User Input File or assembly name 9o3db28v.dll, or one of its dependencies, was not found."

    (the file name is random and changes on every installation attempt).  Any suggestions?  Do you think removing the .NET Framework might help?  The user is a local administrator and has rights to the user and system Temp folders.

    - Steve Yates
    - ITS, Inc.
    - DUNGEON MASTERS do it any way they feel like.

    ~ Taglines by Taglinator 4 - www.srtware.com ~
  • Thanks! I had an XP machine in .NET confused state for some time now (can't install, can't un-install...) and this fixed it.


Page 5 of 19 (280 items) «34567»
Leave a Comment
  • Please add 6 and 2 and type the answer here:
  • Post