If you use Oracle VirtualBox on a Windows host machine you will probably already be aware that Hyper-V (Microsoft's equivalent virtual machine software) prevents VirtualBox from using the hardware virtualization features of your system. The hardware virtualization features will be called either VT-x or AMD-V depending on your CPU.
If you don't use Microsoft Hyper-V you can disable it:
- Open the Turn Windows feautres on or off application
- Uncheck the Hyper-V item and it's sub-items
- Restart the device
Since April 2018 Windows 10 now includes security features called Core Isolation and Memory Integrity which use virtualization technology to keep important system processes separate from other processes, a technique is often referred to as sandboxing.
The benefit of having Memory Integrity active is that a malicious program will be unlikely to gain access to memory used by the protected processes.
The unfortunate side effect of using the Memory integrity feature is that VirtualBox (and other third party virtual machine software) will be unable to use VT-x or AMD-V features.
If you upgraded to the April 2018 version of Windows 10 the Memory Integrity feature is probably disabled but new installations and future updates are likely to enable it by default, I encountered the problem while testing a Windows Insider preview version.
Take a look at this How-to-Geek article for a detailed description of the features.
If you need to switch off the Memory Integrity feature:
- Open Windows Security (formerly Windows Defender)
- Open the Device Security section
- Click/tap the Core isolation details link
- Turn off the Memory Integrity toggle switch
- Restart the device when prompted (the setting change may not be applied if you decline to restart when prompted)
With Memory Integrity and Hyper-V disabled you should be free to run Virtual Machines with full hardware acceleration support in VirtualBox.