Not all third party devices, features, or products can interoperate with Fault Tolerance.

For a virtual machine to be compatible with Fault Tolerance, the Virtual Machine must not use the following features or devices.

Table 1. Features and Devices Incompatible with Fault Tolerance and Corrective Actions
Incompatible Feature or Device Corrective Action
Physical Raw Disk mapping (RDM). With legacy FT you can reconfigure virtual machines with physical RDM-backed virtual devices to use virtual RDMs instead.
CD-ROM or floppy virtual devices backed by a physical or remote device. Remove the CD-ROM or floppy virtual device or reconfigure the backing with an ISO installed on shared storage.
USB and sound devices. Remove these devices from the virtual machine.
N_Port ID Virtualization (NPIV). Deactivate the NPIV configuration of the virtual machine.
NIC passthrough. This feature is not supported by Fault Tolerance so it must be turned off.
Hot-plugging devices. The hot plug feature is automatically deactivated for fault tolerant virtual machines. To hot plug devices (either adding or removing), you must momentarily turn off Fault Tolerance, perform the hot plug, and then turn on Fault Tolerance.
Note: When using Fault Tolerance, changing the settings of a virtual network card while a virtual machine is running is a hot-plug operation, since it requires "unplugging" the network card and then "plugging" it in again. For example, with a virtual network card for a running virtual machine, if you change the network that the virtual NIC is connected to, FT must be turned off first.
Serial or parallel ports Remove these devices from the virtual machine.
Video devices that have 3D activated. Fault Tolerance does not support video devices that have 3D activated.
Virtual EFI firmware Ensure that the virtual machine is configured to use BIOS firmware before installing the guest operating system.
Virtual Machine Communication Interface (VMCI) Not supported by Fault Tolerance.
2TB+ VMDK Fault Tolerance is not supported with a 2TB+ VMDK.