Enabling VT on an Intel EM64T Systems for ESX Server 3
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Enabling VT on an Intel EM64T Systems for ESX Server 3


Article ID: 334121


Updated On:


VMware vSphere ESXi


An ESX Server is running on a VT-capable Intel EM64T processor, but when trying to power on a 64-bit guest, the following error message is displayed:

This CPU is VT-capable, but VT is not enabled (check your BIOS settings).


VMware ESX Server 3.0.x


To resolve this issue:

  1. VT must be enabled in the host system BIOS. The feature might be named VT, Vanderpool Technology, Virtualization Technology, VMX, or Virtual Machine Extensions. You might find this setting under a Security screen in the BIOS.

  2. The VT setting is locked (either on or off) at power on. After enabling VT in your system BIOS, you should first save your changes to the BIOS settings and then turn off power to the system. When you turn the system on again, your changes will take effect. If you simply reboot the system without turning it off, VT will not be enabled.

  3. Once you have power cycled the system, confirm that your system is capable of running 64-bit guests by booting from a CD containing the CPU Compatibility Tool included on the ESX Server 3.0 CD-ROM in /images/cpuid.iso.

  4. Some system vendors ship VT-capable systems without the ability to enable VT in the system BIOS. If you cannot find a way to enable VT in the system BIOS, contact your system vendor. An updated BIOS might be available.