Remove the .NET Framework Assistant 1.0 from Firefox
The newest (3.5 SP1) .NET installs an extension (Microsoft .NET Framework Assistant 1.0) for Firefox (you guessed right: without asking) and even alters the user agent. To maximize “user friendliness”, the uninstall button is inactive. However, regedit helps. Check out “HKEY_LOCAL_MACHINE\SOFTWARE\Mozilla\Firefox\extensions” and delete the key. Other extensions with inactive install buttons, like Google Gears, might be present here as well. That takes care of the unwanted extension, which leaves the user agent. That one can be cleared through deleting “general.useragent.extra.microsoftdotnet”; “microsoft.CLR.clickonce.autolaunch” seems to be of the same origin.
The extensions’ files are located here: \WINDOWS\Microsoft.NET\Framework\v3.5\Windows Presentation Foundation\DotNetAssistantExtension\ when everything else is disabled/deleted, you might want to say goodbye to these files too.
Please also browse through the comments, there are some great & helpful additions. Thanks for that! Obviously I wrote this from the perspective of a Windows XP SP3 (x86) user, while more systems (not necessarily in the exact same way) are affected, of course.
I just installed Firefox on a machine with .NET 3.5 SP1 already present – Firefox 3.0.6 was immediately “equipped” with the Assistant. There is no escape! :P
Oh happy day – the “long and complex”/manual method described above, to remove the .NET Framework Assistant 1.0 from Firefox again, might no longer be necessary. Microsoft itself released a fix (apparently on 2009/May/06) to enable the originally disabled uninstall button again.
In .NET Framework 3.5 SP1, the .NET Framework Assistant enables Firefox to use the ClickOnce technology that is included in the .NET Framework. The .NET Framework Assistant is added at the machine-level to enable its functionality for all users on the machine. As a result, the Uninstall button is shown as unavailable in the Firefox Add-ons list because standard users are not permitted to uninstall machine-level components. In this update for .NET Framework 3.5 SP1 and in Windows 7, the .NET Framework Assistant will be installed on a per-user basis. As a result, the Uninstall button will be functional in the Firefox Add-ons list. This update will also make this version of the .NET Framework Assistant for Firefox compatible with future versions of the Firefox browser. To properly update the .NET Framework Assistant, this update must be applied while the extension is enabled in Firefox. To remedy the result of installing this update while the extension was disabled, uninstall the update, re-enable the extension, and reinstall the update. Updates to the .NET Framework Assistant may include updates to the Windows Presentation Foundation Plug-in for Firefox causing it to be enabled upon its initial update.
This is what happened after above patches were installed:
The uninstall button is now active as promised and the .NET Framework Assistant version was raised from 1.0 to 1.1. Pressing “Uninstall” successfully clears the user agent too/reverts it to its former state. Happy endings…