Virtualbox + Windows 8.1 + AMD issue

[JoshAhWah]

I upgraded from Windows 8 to Windows 8.1 and now when I try to boot any 64-bit VMs they all say

VT-x/AMD-V hardware acceleration is not available on your system. Your 64-bit guest will fail to detect a 64-bit CPU and will not be able to boot.

I updated to 4.3.0 and no luck. Also uninstalled, rebooted, reinstalled to see if that would help. Hyper-V and VMWare have both been tested and work fine. I have the latest BIOS/UEFI installed for my motherboard. I ensured that Virtualization was enabled in my BIOS.

Any ideas would be great!

Specs:

Code: Select all

		Operating System
			Windows 8.1 Pro 64-bit
		CPU
			AMD FX-6100	41 °C
			Zambezi 32nm Technology
		RAM
			16.0GB Dual-Channel DDR3 @ 793MHz (11-11-11-28)
		Motherboard
			ASRock 970 Extreme3 (CPUSocket)	40 °C
		Graphics
			2036 (1600x900@60Hz)
			SA300/SA350 (1920x1080@60Hz)
			W1943 (1360x768@60Hz)
			1023MB NVIDIA GeForce GTX 560 Ti (NVIDIA)	65 °C
			1024MB NVIDIA GeForce 210 (NVIDIA)	40 °C
			ForceWare version: 331.58
			SLI Disabled
		Hard Drives
			1863GB AMD 2+0 Stripe/RAID0 SCSI Disk Device (RAID)
			111GB KINGSTON SV300S3 SCSI Disk Device (RAID)
			1863GB Western Digital WDC WD20EARX-00PASB0 SCSI Disk Device (RAID)

[BillG]

Is Hyper-V still installed? Hyper-V grabs the hardware virtualization at boot time.

[JoshAhWah]

That was easy. I should point out that Hyper-V was never installed before I had this problem. I actually installed it to test to see if virtualization was working at all, and then when I removed it (per your suggestion), vbox is working again. Thanks for your suggestion!

[ExPeacer]

Hy!

I tried the same method, but still not working. 8.1Pro x64 - FX8320 - M5A97 R2.0. Everything enabled, in VmWare I can boot x64 kernel based distros (yes, I uninstalled VmWare and rebooted the system too).