I just tried to troubleshoot or pinpoint the problem a bit further. It seems, this issue is _not_ related to the USB mic (like I read on the internet several times). I disconnected the A50 headset from my computer and used a cable-connected 3,5 inch headset which I had here and I can still reproduce this issue. Whenever I press the push-to-talk key the game freezes for around a second.

Just saw, that the video was still in draft, published it now, sorry!

Does it happen if you launch MP mission preview from 3DEN?

Yes, the problem can be reproduced in aN MP 3DEN editor mission as well.

What I did:

1. Go to Multiplayer
2. Host server
3. New 3D Editor
4. Place one ammo bearer unig on an otherwise empty/default Altis map (no scripts or other additions made)
5. Play the Scenario in MP
6. Reproduce the freeze when pressing the push to talk key

Followed your steps exactly on 2.02, no cigar. Try uninstalling your headset drivers maybe and try again.

I did that already. I also verified the files of arma in strand and also rolled back to the last windows version. Nothing helped.

I mean, is there some way to debug what could be the reason for auch a freeze when the push-to-talkis hit? Maybe some flag I can start arma with to get some more info on the RPT?.

Okay, now I did the following as well:

• Reinstall ArmA 3 (not verifying the local files with Steam, only, which I did already, a complete, fresh install, apart from the profile)
• Uninstall all audio device drivers apart form the ones which are connected (the 3,5 inch cable headset as well as my monitor, which is connected via HDMI, and a virtual device from NVidia)
• Uninstalled a separate sound card from the computer (via PCIe) and used the onboard audio connectors from my mainboard

That is now the most simple setup I can imagine (audio related). Apart from re-installing Windows I don't see what I can do anymore, at least not yet :(

try making new soldier profile
if no change try remapping push to talk to some other key see if this helps

Did the remapping thing already. I just tried it again with a fresh soldier profile (and remapping from tab to alt gr for the push-to-talk key). Have the same issue still :(

Okay, I just tried to reproduce the error on another computer ( a little notebook, bad fps bud good enough to see if the screen freezes).

Both, with and without the USB headset the game didn't freeze when I press the default push-to-talk key.

Now, the only difference between the two computers I can think of is, that the one where the problem occurs has an insider build of Windows (I might have failed to mention that already, sorry for that :(). The build on the computer which has this issue is 21327.1000. Is there any way you could check if that is related somehow? Otherwise I'm now completely lost on how to find out what difference causes such a strange issue :(

If it matters as well, it's Windows 10 Pro.

so you are practically running beta version of windows? quick search brings this “We’re working on a fix for an issue where some devices with Realtek network adapters running driver version 1.0.0.4 may experience intermittent loss of network connectivity.” which sounds like something that might cause freezes.

I'm using an intel ethernet and an intel wireless adapter, so it _might_ be not related, but still could be. Would be interesting to know how we could verify that? I mean, I had this problem with the prior insider build as well (however, the issue might be in this build already). Like I said, other games with in-game voice chat works as well, so it might be a specific way how arma interacts with the network or audio devices? I might also open an issue with Microsoft as well, so maybe they can confirm it is this error.

Update:
Even with the last Dev channel insider preview (21332), the problem persisted.

Trying now the latest version, 21337, which has one interesting change:

We fixed an issue in recent flights that could result in some games freezing after locking and unlocking your PC while the game was in full screen mode. This issue may also have resulted in freezes after ALT + Tab.

Not sure, if it was actually this specific fix they made, but now it works again :D