Decklink Studio 4k missed with video desktop 10.9.9

Just upgrade to video desktop 10.9.9 and doesn't recognise my Decklink Studio 4k.
Back to 19.9.7 and goes normal..

any ideas?

my system

I7 6700k
32 ram
windows 10

Same here with DeckLink Duo 2 on Windows. It's still in device manager but with warning sign. Seems to be an issue with the signature of the driver BlackmagicIO.sys in 10.9.9.

Same here with my Decklink 4k, too. Only 10.9.5 drivers recognize my device under Windows 10.

I have the same problem with the Decklink Mini Monitor 4K. System doesn't recognise my DeckLink
Mini Monitor 4K.

My system is:
Windows 10 Pro 64bit, Version 1709
Processor AMD Ryzen 7 1700X
RAM 32,0 Gb

Can you disable secure boot and see if this persists?

Disabled Secure Boot and did a fresh Windows install. Now 10.9.9 is working. But why was is working with 10.9.7?