SharePoint 2010: FSSPUsernameFilter.dll failed to load

While I was restoring my SharePoint farm I got this little error:

"The HTTP Filter DLL 'C:\Program Files\Microsoft Forefront Protection\FSSPUsernameFilter.dll' failed to load. The data is the error."

"The data is the error" sounds like something straight from The Matrix, but don't worry, we're still talking about Microsoft Tools. So how do you fix that?

Solution A)

1. Check which account is used to run the IIS pool for your SharePoint WebApp.

2. Check the permissions on your Forefront installations directory and grant full access to the mentioned account.

3. Maybe you also need to grant full access to the "

FSSUPUsernameFilter.dll

". But this is something you have to test for yourself. Sometimes it works without permissions on file level, other times it did not work for me.

Solution B)

1. Remove the filter:

2. Deactivate the anti-virus scan:

Depending on your users, the second solution might not be the smartest idea, but at least you can get the farm running while you are maybe reinstalling Forefront.

Solution C)

Reinstall Forefront. This is your last resort. Make sure that every Forefront file is removed and install the application again.

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