STLink virtual com port driver digital signature verification problem

[Peeters.Bram]

After connecting a STN32H735G-DK board to my windows 7 pro pc, the com port driver gives an error "Windows cannot verify the digital signature for the drivers required for this device. A recent hardware or software change might have installed a file that is signed incorrectly or damaged, or that might be malicious software from an unknown source. (Code 52)". In the driver info tab it says the digital signer is STMICROELECTRONICS (GRENOBLE 2) SAS. Not sure how all the driver signing stuff works in windows, but is it posssible I need to add a root certificate somewhere ? Other suggestions ? (I also tried uninstalling the driver and installing en.stsw-stm32102.zip, but this does not seem to change anything)

[Peeters.Bram]

Additional observation: it seems the st driver is a wrapper around a microsoft provided usbser.sys driver, which is unsigned. Maybe that is part of the problem ?

Edit: in the meantime I also tried it on another windows 7 pc where it actually works. On that PC the usbser.sys file is an older version ( 6.1760.1.17514 (win7sp1_rtm.101119-1850)) that is signed by microsoft. So it seems i have installed an update at some point in time on the problematic PC that makes usbser.sys unsigned.

Copying over the older file "fixed" the problem.