Microsoft Volume Licensing customers that’re using Microsoft Enterprise Desktop Virtualization as an integral part of the Microsoft Desktop Optimization Pack (MDOP) need to make sure that antivirus maskings are in place for MED-V file types in order to ensure optimal user experiences. In order to prevent antivirus activity from affecting the performance of the virtual desktop, it is recommended to exclude the following Virtual Machine file types from any antivirus or backup processing running on the host: *.VHD, VUD, VSV, CKM, VMC, INDEX, EVHD