On a Citrix XenApp 5 environment a user reported that he was unable to start a Full Screen session on a Dual Monitor Configuration.

He received this error message:

foutmelding (2)

Citrix has a KB Article: “How to Allow More Memory for Session Graphics on Windows Server 2003” that explains exactly how we can solve this.

We need to change the MaxLVBMem registry value and we can use the Excel Sheet from the KB Article to calculate the proper value.

Please don’t set this value too high because a higher value means you will restrict other kernel memory pools.

You also need to deny the SYSTEM account the SetValue permission on the HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management key to prevent the Citrix IMA service from overwriting the new value.

So I wrote a small PowerShell script to change the permission and set the value: