Low colors on Terminal Server/Citrix/2X sessions

Have you just bought a very high-resolution monitor or have attached two or more hi-res monitors to your Terminal Server/Citrix/2X Client, than you may experience a degradation in color depth on the monitorscreens.

For this to happen, you need Terminal Server 2003

- with Service Pack 2

or - a Terminal Server with hotfix 918679 is installed.

To request the hotfix to fix is issue:

- Go to http://support.microsoft.com/hotfix/KBHotfix.aspx?kbnum=942610&kbln=en-us

You will have to select the appropiate Windows 32/64-bit version ,the right language and fill in your e-mail. The downloadlink will be send to you shortly.

After installling the hotfix, you need to restart the server and

afterwards you have to change the value of AllowHigherColorDepth (reg_Dword) located at HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server from 0 (zero) to 1 (one).

If the key doesn't exist, please create it at the correct registrylocation.

The Micorosoft KB-article has the following title:

The color depth is unexpectedly changed to 8-bit when a high screen-resolution setting is used in a terminal-server session that is connected to a Windows Server 2003-based computer.

and can be found here.