virtualbox.org

Uninstalling KB3045999 solved this problem for me.

Thanks!

Also works for me, thank you!

Here's my vote for uninstalling KB3045999. Same problem, uninstalling that update solved it. Prior, a couple of MS updates were failing to install. Apparently, they're struggling with getting something right.

Thank you a lot.
It restart working.

Is there another solution for systems that can't remove this update due to company policy?

Wait till Microsoft fixes their bugs...

Please could you try the latest Windows test build (>= r100091? It contains a fix which should allow you to install the Microsoft hotfix which is highly recommended as they contain important security fixes. Thank you!

vampdrgn3 wrote:Is there another solution for systems that can't remove this update due to company policy?

Another option is to downgrade VirtualBox to 4.3.12, which is the last version before security hardening was added. Evidently the bug has something to do with that. I've tested 4.3.12 and it works with KB3045999 installed.

skinerd wrote: Another option is to downgrade VirtualBox to 4.3.12, which is the last version before security hardening was added. Evidently the bug has something to do with that. I've tested 4.3.12 and it works with KB3045999 installed.

The issue with rolling back to an earlier version of VB is of course it circumvents the security measures VirtualBox has gone to the trouble of installing for their users and 4.3.12 doesn't support some of the recent versions of Linux.

I did

- install VirtualBox 4.3.28
-- 1. VirtualBox-4.3.28-100309-Win.exe
-- 2. Oracle_VM_VirtualBox_Extension_Pack-4.3.28-100309.vbox-extpack
-- 3. VBoxGuestAdditions_4.3.28.iso
- install Microsoft security update KB3045999

and noticed: Virtual machines can be started again.
Host: Windows 8.0 x64

No need to delete anything. It is necessary to include in the BIOS virtualization

same problem on windows 10!!! any help?

I just uninstalled 4.3.12 and installed 5.0.6 and it's working for me.

KRZ wrote:Uninstalling KB3045999 solved this problem for me.
I did
- install VirtualBox 4.3.28
-- 1. VirtualBox-4.3.28-100309-Win.exe
-- 2. Oracle_VM_VirtualBox_Extension_Pack-4.3.28-100309.vbox-extpack
-- 3. VBoxGuestAdditions_4.3.28.iso
- install Microsoft security update KB3045999

It only solved the problem temporarily. When I upgraded my PC, the problem happened again