AMD-V stopped working suddenly

[SuperVeloce]

Hello to all helpful folks here,
I have an unusual problem with my existing setup (windows 8.1). I ran linux virtual machine for months normally, now I get errors E_FAIL (0x80004005) and verr_svm_no_svm (if I remember correctly) and now my 64bit virtual machine is non bootable. There was no change in bios version or chipset drivers (at least that I know).

Can this be Windows problem? I don't have any option in bios for amd-v, but it worked superbly until yesterday (set on 4 cores for my VM). Only thing I remember changing in recent days was removing those microsoft updates for windows 10 reservation and upgrade. Yesterday I re-set bios to stock settings, reinstall amd chipset drivers and even reinstall those updates from microsoft (desperate move).

It's an Asus laptop with A6-3420m with 8gb ram (cpu upgraded a year ago).

edit: even in cpu-z there is no sign of amd-v

[SuperVeloce]

Ok, update. I tried to disable and re-enable hyper-v in windows features (under "programs and features"), to no avail. After that (and many system reboots) I just disabled it and left it at that.
But VM now works!
To my very limited knowledge there is some other process in windows, locking amd-v feature, because if I enable it again it stops working (and not even showing in cpu-z).

This thread can be locked now. Thanks for reading about my problems

[Perryg]

To my very limited knowledge there is some other process in windows, locking amd-v feature,

And the most common critter is hyper-v which does not play well with any other hypervisor or anything else that might require VMX for that matter.