Story time?

So when Microsoft switched to New Teams, all of my desktop users with triple monitors started having this problem where a display would go black while interacting with Teams. Not just when joining a Teams meeting. Simply dragging the Teams window around could cause one of the monitors to go black. It very much felt like an issue that disabling Hardware Acceleration in Teams would solve. But as we all know, MS offered that option in Classic Teams but not New Teams. As an aside, this issue also occurs with with New Outlook. But nobody really uses that.

After some digging and testing, I figured out how manually disable hardware acceleration in New Teams by editing the "Local State" file in the EBWebView folder. This fixed the problem. For around 1.5 years anyway. Then Microsoft stopped respecting the setting to disable hardware acceleration in the Local State file and the issue came back for my triple monitor users.

So back to the drawing board. I ended up procmon-ing the hell out of everything to find out what files and settings were in play when Teams was both launched and when the issue occurs. Then doing literal line by line registry setting comparisons when I managed to find some interesting behavior. One day I stumbled upon a solution involving changing a bit value for an Intel video setting to disable something. I'm not 100% what it disables, as there isn't much good documentation from Intel on the specific bit value change I made. There is a fair amount of chatter involving changing another bit value within the same registry value to disable Adaptive Brightness.

Onto the change. This solution was specifically targeted to fix an issue with displays going black while using New Teams or New Outlook while using integrated Intel video. I've only tested this with computers using integrated Intel video. I don't know that it will help with your issue since the symptom described in your post is very different. But I suppose it does not hurt to give it a try. Perhaps others might find this helpful.

Browse to the following registry key

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class{4d36e968-e325-11ce-bfc1-08002be10318}

Expand this key. You will find some number of keys named 0000, 0001, 0002 and so forth. If you have multiple video adapters, virtual or physical, you will have more numbered keys. Browse the numbered keys until you identify the one related to your video card. Most commonly it will be 0000. But it is system dependent.

Within the correct numbered key, locate a DWORD Value named: "FeatureTestControl". For the computers in my environment, the value was 1200 in Hex which translates to 4608 in decimal. The solution is to increment the value of the last bit by 1. So in my case, changing the value from 1200 to 1201. It was easier for me to change via PowerShell using decimal. So when I scripted the change, it was 4608 to 4609.

I want to be very clear here. I AM NOT TELLING YOU TO CHANGE THE VALUE TO 1201 or 4609. The instructions are to identify your current value and increment the last bit by 1. If your current value is 8200, change it to 8201. If your current value is 9240 change it to 9241.

Reboot is required for change to take effect. Obviously this is a very blunt instrument fix. Likely is some general negative performance impact for graphics as a result of this. But given the criticality of Teams in our environment, it was worth any unknown tradeoff.