Virtual box intel vt-x error

Question

I tried to access the acceleration tap under system under settings and I can not. The tab is greyed out like their is no data available.

Answer 1

If the corresponding Virtual Machine is running then the options under acceleration tab(Settings->System->Acceleration) would be grayed out.

So poweroff the virtual machine in-order to enable Hardware Virtualization(intel vt-x).

Answer 2

If you have :-

1. VirtualBox's error - something likes " VT-X is not available".
2. Host os is 64 bits with more than 4 GB of ram.
3. Guest os is 32 bits

Lest's try to reduce VirtualBox's base memory to be under 4 GB.