Note, these are preliminary findings posted as a cautious warning to other laptop users who put their capture cards in Thunderbolt expansion boxes.
I advice you to check things if you have the same or similar setups.

Yesterday we ran into problems as the camera inputs froze soon after going live. My crew rebooted and started again, but the inputs froze after about 30 minutes. vMix kept streaming so we got audio and could repair the production afterwards.

After spending a day looking for a cause I am convinced it is related to recent Window updates affecting Thunderbolt. Perhaps only related to Asus GL502VM-FY211T. So far a sister machine with 6:th gen i7 seems to work fine (can't remember the model number). I have 6 similar PCs, but only checked with 4 so far.

These laptops have the "Thunderbolt controller - 15BF" listed in the device manager. Control panel Programs and features include "Thunderbolt software 16.2.52.250". We use both Firmtek TB2 expansion boxes with Apple's TB2-TB3 adapter and a Sonnet TB3.

Up until I noticed the problem Windows automatically recognized the Thunderbolt device and made the capture card devices available when the Thunderbolt cable was connected to the PC. Now the laptops with issues has to be connected, dis-, and then re-connected before the Thunderbolt device was recognized. But preliminary tests still result in freezing and/or problems to close vMix/Windows.

My current fix, that after some brief tests seems to work, is to:
NOTE perhaps not to recommend, but I need to get things working...
- disconnect the Thunderbolt cable
- uninstall the Thunderbolt software
- reboot
- install TBT_WIN10_64_17.4.77.400
- reboot

In my case with TB3 only I still have to Scan for hardware changes in the device manager. And with the TB3-TB2 adapter I have to twice dis- and reconnect the cable from the adapter.

Hopefully few other users are affected, and future Window updates will fix things up.

If you have any questions, comments, or similar experiences I am here.

Not vMix related but I'm running the Windows 10 preview (Work OS) and had several Thunberbolt issues lately with My HP Elitebook 850 G5.
Not recognising my USB devices connected to my Thunderbolt Docking. A full shutdown and removing power from the docking helps.

Besides that I have in my Music OS (same laptop) issues with same model Thunderbolt Docking but at home.
Sometimes my audio (ASIO USB interface connected to Thunderbolt docking) freezes for 2 seconds and then continues like nothing happened.

Think I have this for about 2 weeks now.
So I do agree something is going on with Thunderbolt an Win 10 (Pro in my case)

Richard, thanks for starting this topic. I just purchased a Magewell Pro capture Quad SDI to use in an Akitio Node Lite and having a similar issue. Both Vmix and Capture Express are not seeing or detecting any of the SDI inputs.
I'm using an Asus ROG GL502VMK and am on Win 10 Home Version 10.0.17134 Build 17134.

Interesting thing... last week, I was trying a BMD Decklink Duo 2 and it was working fine in the same enclosure. I just returned it because it was having trouble recognizing a couple of my Marshall cameras at 1080p60.

Now I also notice I see the 4 Quad SDI ports in device manager, but no aikito listed anywhere. Though I believe I saw it listed last week. Perhaps I'll try reinstalling the akitio driver before the t3 software you describe.

Regards,
Henry

EDIT: Hey just found a clue. Win10 added some kind of Thunderbolt protection now, could this be it?
https://docs.microsoft.c...otection-for-thunderbolt

I did read somewhere that there is a BIOS setting that enables or disables T3 ports, sorry can't recall where.
I did fix my own problem. My mistake, in my rush I dl'ed the magewell drivers for Win7,8 as it was top of the list. I uninstalled those, and installed the Win10 versions and my drivers were recognized and authorized just fine. Card working great now.
Good luck. I'll be monitoring my thread in case I see your issue crop up.

Regards,
Henry