How to force a single session or allow multiple Remote Desktop sessions per user

Remote Desktop/Terminal Services has two settings for multiple sessions. You can either allow multiple sessions per user (in which case if you log in twice, you'll get two sessions), or force a single session per user (in which case you can only log in once and subsequent sessions will be redirected to the original session.

To change this setting, you'll need to perform a registry change. The following steps describe the process:

1. Start Registry Editor (by default, this is located at c:\windows\regedit.exe).

2. Go to the following registry key:

   HKEY_LOCAL_MACHINE\
       System\CurrentControlSet\Control\TerminalServer

3. If the fSingleSessionPerUser value doesn't exist, create a new DWORD value named fSingleSessionPerUser
4. Open the fSingleSessionPerUser value. The possible values for this setting are as follows:

   0x0

   Allow multiple sessions per user

   0x1

   Force each user to a single session

5. Enter the new setting, and then click OK.