When users logoff from the system (published desktop) the key HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows Messaging Subsystem is not synced and cannot be found in the ntuser.dat on the profile share, although the key is not listed in any registry exclusion list.
This prevents roaming of the Outlook profile and users will be prompted to create a new profile upon the next logon when they open Outlook. As long as the user has the same session Outlook can be opened multiple times without any issues and also the registry key is still present.The McAfee antivirus is causing the issue. Add UserProfileManagement.exe to the list of Low-Risk processes.