Server 2012/2008 R2 unlike their predecessors, comes with the multiple remote desktop session restriction enabled. If you are working with several colleagues, you will kick each other from the server. This is really annoying.
Just as the earlier versions of Windows Server you have the possibility to have two RDP sessions at one time. The restriction is one logon for one account.
All you have to do is change the following Registry key:
Change the key “fSingleSessionPerUser” (Right Click -» Modify) and replace the Value data 1 to 0.
No reboot is required. You are now able to connect with 2 sessions at the same time.