Windows 10 fails after installing VB5 guest additions

[geoffd]

Windows 10 64 bit under VB5. On reboot after installing the VB5 guest additions it fails because of an unsigned driver - vboxguest.sys Error Code 0xc0000428. I installed the VM using a 4.x version of VB and am pretty sure I had that versions guest additions running OK. The only change is that I have now upgraded to VB5 and received a prompt to install a new version of guest additions which I duly did and now have a VM that won't start.

[geoffd]

Have uninstalled the VB5 guest additions and have regressed to VB 4.3.30 and installed its guest additions and that fails on reboot with the same error. The error text is 'The operating system couldn't be loaded because the digital signature couldn't be verified'.

I guess I was mistaken about it being specific to VB5 but I can't be sure what version of VB I was running previously.

[JanMolnar]

The issue seems to be related to topic #69164 and a few others.
There is also ticket #14263.