I recently ran into an issue where Outlook was not able to be launched from a XenDesktop session when that application was delivered via XenApp and the Online Client Plugin. The error was: "Cannot Start Microsoft Outlook." Also noted was when logging into the XenApp server using a published desktop the user also was unable to launch the Control Panel mail.cpl. The error was: "Your system needs more memory or system resources. Close some windows and try again."

The user having the issue was utilizing a Mandatory Profile created in Windows 7 that was launching from a shared network location. When running Outlook as Administrator the application launched correctly.

An attempt was made to use a PRF to auto configure the Outlook Profile but this produced the same error.

Outlook also failed to launch using any of the typical command line switches such as /resetnavpane, /safe:1, /safe, etc.

Click below to read more about the solution to this issue.

<!--more-->When removing the Mandatory Profile from the users AD Account and clearing the profile off of the XenApp server Outlook launched correctly.

The cause of this issue was that the user was unable to access a necessary key in HKCU that stores Profile Information. This was the reason mail.cpl was unable to launch and thus so was Outlook. It was preventing the creation of the profile for that user.

The solution was to rename the NTUSER.man file back to NTUSER.dat, load the hive into the registry and rename or delete the following key:

<strong>HKCUSoftwareMicrosoftWindows NTCurrentVersionWindows Messaging Subsystem</strong>

After doing this, the hive was unloaded and the file renamed back to NTUSER.man and copied back into the Mandatory Profile folder in the shared network location.

After re-launching Outlook both from XenDesktop and XenApp it was able to successfully start and a profile was created. In reviewing HKCU in the registry it was noted that a new Key was created to replace the one removed from NTUSER.man and it was accessible to the user. The mail.cpl applet was also able to be launched by the user.