From my team:
This could be a permission issue. He can try the following to see how it goes.
1, Disable UAC in citrix server and CRM server
2. As a test, give 'everyone' group full control to MAS folders at the server
3. As a test, give 'everyone' group full control to MAS workstation folders at the Citrix server
3. Reboot Citrix server
4. Reboot MAS server