We're using a Terminalserver Farm on Windows Server 2008 R2 with Hyper-V and Firefox as our standard browser. Since version 50 we have an issue with font rendering of some sites. Cleartype is active in Windows and working correctly for all other apps than Firefox. In Firefox Hardware Acceleration is active, if can be used. On the terminalserver it is not supported as seen in about:support. We've configured the preference "gfx.font_rendering.directrewrite.force-enabled" to true and everything is fine. Yesterday we've updated to Version 51.0 and the Preference is set to true but does not work. Is this a bug or is this a normal behavior? Any help would be very nice. Regards, Alex