Firefox window contain, is not seen by UltraVNC Viewer

[DenisPSA]

Hi all,
I'm experiencing an issue using UltraVNC with Firefox: on the UltraVNC Server machine (Winfows 10), Firefox 60 is loaded and works as expected. But on the UltraVNC Viewer machine (Windows 10) I can't see the contain of the Firefox window, no URL field, no item to load the menu/option and so on, no toolbar. Just a white window. No problem with IE or CH.

Could anybody help me to understand what's wrong please?

Many thanks.
Denis

[SkyBeam]

I did never have this issue yet but it might be related to hardware acceleration of Firefox which uses GPU to render the window content.
Try temporary disabling hardware acceleration for debug purposes:

• Menu -> Options
• Scroll down to "Performance"
• Uncheck "Use recommended performance settings"
• Uncheck "Use hardware acceleration when available"

Or browse about:config and switch layers.acceleration.disabled to true.

Note: Neither chrome nor IE is using hardware acceleration to draw window contents as of my knowledge, so they might not be affected. Also it's recommended to re-enable hardware acceleration after testing. I suspect it might be rather an issue about screen capturing UltraVNC uses in conjunction with your graphics drivers. If disabling HW acceleration solves the issue you might want to update to the latest graphics drivers to resolve the problem.