Uninstall “Microsoft .Net Framework Assistent” Firefox add-on

Windows Update comes with a sort of surprise this time for us firefox users. Microsoft .Net Framework 3.5 SP1 installs an extension named “Microsoft .Net Framework Assistant 1.0“. The add-on adds support for “Clickonce” and the ability to report installed .Net versions to the web server. Well, I suppose you neither like Microsofts way to distribute the add-on (no uninstall routine, the uninstall button is deactivated) nor the way Firefox handles access to your browser. So let’s get rid of it.

Uninstall Microsoft .Net Framework Assistent
Screenshot of the Firefox “add-ons dialogue”. The uninstall option is disabled.

Uninstall the “Microsoft .Net Framework Assistant 1.0” add-on

  1. Hit “Start › Run › “regedit” – STOP! and hit “CTRL + SHIFT + ENTER” (“Run as Administrator”)
  2. Navigate to “HKEY_LOCAL_MACHINE\SOFTWARE\Mozilla\Firefox\extensions
  3. Right click on the entry “{20a82645-c095-46ed-80e3-08825760534b}” and delete it
  4. Navigate to “HKEY_LOCAL_MACHINE\SOFTWARE\MozillaPlugins
  5. Right click on the subkey “@microsoft.com/WPF,version=3.5” and delete it
  6. Open Firefox and enter “about:config” in the address bar
  7. Filter for “general.useragent.extra.microsoftdotnet” and “microsoft.CLR.clickonce.autolaunch” and delete/reset the strings (if applicable)
  8. Restart Firefox and goto “C:\Windows\Microsoft.NET\Framework\v3.5\Windows Presentation Foundation
  9. Rename the folder “DotNetAssistantExtension” to “DotNetAssistantExtensionOld” and the file NPWPF.dll to NPWPF.dll.old (you can delete the folder and the file later if you don’t encounter problems)

This worked for me. I take no responsibility ;-)

9 thoughts on “Uninstall “Microsoft .Net Framework Assistent” Firefox add-on”

  1. is this add-ons good for firefox or no
    is it bad for firefox . plz tell me what it the problem with this add-ons

  2. Someone should figure out a way to make the .net addon add software that has the computer check for updates every minute!

  3. Concerning the comments about whether it’s good or not, I’d refer readers to Annoyances.org’s take on it: “this update adds to Firefox one of the most dangerous vulnerabilities present in all versions of Internet Explorer: the ability for Web sites to easily and quietly install software on your PC.” I’d say that’s bad… ;)

    Reason I’m back looking for uninstall directions is this rose from the dead after installing Firefox 3.6. In fact, many other add-ons appeared that weren’t previously listed after installing 3.6. It apparently is much more strict in regards to add-ons, and is helping to expose those add-ons that have “snuck” on. Prosit!

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