Uninstalling the Clickonce Support for Firefox

A couple of years ago we heard clear feedback from folks that they wanted to enable a very clean experience with launching a ClickOnce app from FireFox. James Dobson published FFClickOnce and got very good reviews, but we had many customers that wanted ClickOnce support for Firefox built into the framework… so in .NET Framework 3.5 SP1 we added ClickOnce support for Firefox! This made ClickOnce apps much more accessible to a wide range of customers.

We added this support at the machine level in order to enable the feature for all users on the machine. Seems reasonable right? Well, turns out that enabling this functionality at the machine level, rather than at the user level means that the 'Uninstall' button is grayed out in the Firefox Add-ons menu because standard users are not permitted to uninstall machine-level components.

Clearly this is a bit frustrating for some users that wanted an easy way to uninstall the Clickonce Support for Firefox. But good news! We have a fix in place (enabling each user to uninstall the feature for themselves) and our testing team is making sure that is rock-solid now.. I expect that to be out in the next few weeks. I’ll be sure to post more information on that when I have it.

In the meantime, if you want to disable the Clickonce Support for Firefox here are the steps directly from the dev in charge..

Stop-gap Solution To uninstall the ClickOnce support for Firefox from your machine

1) Delete the registry key for the extension

i. From an account with Administrator permissions, go to the Start Menu, and choose 'Run...' or go to the Start Search box on Windows Vista

ii. Type in 'regedit' and hit Enter or click 'OK' to open Registry Editor

iii. For x86 machines, Go to the folder HKEY_LOCAL_MACHINE > SOFTWARE > Mozilla > Firefox > Extensions

For x64 machines, Go to the folder HKEY_LOCAL_MACHINE > SOFTWARE > Wow6432Node > Mozilla > Firefox > Extensions

iv. Delete key name '{20a82645-c095-46ed-80e3-08825760534b}'

OR alternatively

i. Open a command prompt window (must be 'run as Administrator' on Vista and later)

ii. Copy and paste the appropriate command below and hit 'Enter'

For x86 machines:
reg DELETE "HKLM\SOFTWARE\Mozilla\Firefox\Extensions" /v "{20a82645-c095-46ed-80e3-08825760534b}" /f

For x64 machines:
reg DELETE "HKLM\SOFTWARE\Wow6432Node\Mozilla\Firefox\Extensions" /v "{20a82645-c095-46ed-80e3-08825760534b}" /f

2) Reset the changes made to the Firefox user agent

i. Launch Firefox, go to the Firefox address bar and type in 'about:config'

ii. Scroll down or use 'Filter' to find Preference name 'general.useragent.extra.microsoftdotnet'

iii. Right-click on the item and select 'reset'

iv. Restart Firefox

3) Remove the .NET Framework extension files

i. Go to the Start Menu, and choose 'Run...' or go to the Start Search box on Windows Vista

ii. Type in 'explorer' and hit Enter or click 'OK'

ii. Go to '%SYSTEMDRIVE%\Windows\Microsoft.NET\Framework\v3.5\Windows Presentation Foundation\DotNetAssistantExtension\'

iii. Delete the 'DotNetAssistantExtension' folder and all its contents

"