Update apparently killed browser HDMI output

[Wendell]

My system updated (without me telling it to - it was in sleep mode and updated overnight GRRRRR). Now I find that neither Edge or IE will output audio to a second monitor via HDMI - which I regularly use in doing music contained in a video. However Chrome continues to work OK - which gets me by in the short run. Has anyone else observed this problem with IE or the Edge browser?

[Claude]

Does other software still work as expected ? (I suspect that it isn't a browser related problem, rather an OS problem.

Can you please give version information ?

[Wendell]

KB4039788 was installed last weekend - and I suspect there was an update to the way Adobe Flash is handled, as the website where I'm experiencing the problem is using Flash. Audio programs seem to work fine - that is the output is redirected to the 2nd monitor/TV. I intend to roll back the update next week when things settle down a bit here, and see if that resolves it. Thanks for responding so quickly, and apologies for not replying sooner.