1. VDA will randomly crash with BSOD.
2. All changes in master image machine (with local HDD) will revert back after reboot/shutdown.

Cause 1: 
"PvsVmBoot" is missing from below mentioned registry location
Path: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager
Name: BootExecute
Type: REG_MULTI_SZ

Solution 1:

1. Shutdown the VM.
2. Boot the VM with Hiren’s Boot ISO (http://www.hirensbootcd.org/download/)
3. Launch Mini XP
4. Edit registry with Registry Editor PE (Step 3: https://www.wintips.org/how-to-edit-and-modify-registry-offline/)
5. Expand below mentioned registry location and edit "BootExecute" registry string HKEY_LOCAL_MACHINE\REMOTE_SYSTEM\ControlSet001\Control\Session Manager

1. Verify the same under HKEY_LOCAL_MACHINE\REMOTE_SYSTEM\ControlSet002\Control\Session Manager
2. Close Registry Editor
3. Remove Hiren's Boot CD from boot order and reboot the VM. 

Cause 2:
CtxMcsWbc.sys Driver is not behaving as expected

NOTE: The workaround provided below with effectively disable this driver and leave the VDA in a state that is inconsistent.

This workaround may be used for troubleshooting, but will leave the VDA in an inconsistent state. This driver controls the MCS I/O  Optimization feature The full effect of disabling this driver is not clear at this point. 

Workaround

1. Shutdown the VM.
2. Boot the VM with Hiren’s Boot ISO (http://www.hirensbootcd.org/download/)
3. Edit registry with Registry Editor PE
4. Disable the Citrix MCS cache service by changing the Start value from 0 to 4 from the following sub key:
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\CtxMcsWbc
5. Delete the "CtxMcsWbc" entry in the "UpperFilters" value in the following sub key:
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4d36e967-e325-11ce-bfc1-08002be10318}
6. Unload the System hive from the mounted VHD.
7. Detach the mounted VHD.
8. Start the VM  normally.

Recommendation
Upgrade to XenDekstop 7.15

Problem Cause

Issue with CtxMcsWbc.sys Driver.