Windows XP Concurrent Users in Service Pack 2

Windows XP Professional Service Pack 2 was originally to introduce the ability for users to be logged on at the console and via Remote Desktop simultaneously. This functionality was added in the pre-release (“beta”) versions of Service Pack 2, but was disabled for the final version of Service Pack 2.

However, a workaround exists which restores this functionality.

1. Obtain termsrv.dll version 5.1.2600.2055. The MD5 hash of the file is a77219a971029dc2fb683e8513713803.

2. Enable Fast User Switching and the use of the Welcome Screen.

3. Set the value “EnableConcurrentSessions” to 1 in the following registry key:

   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\Licensing Core

4. Start Windows XP in Safe Mode, rename the existing file as termsrv.was and copy the replacement file to %SystemRoot%\System32 and %SystemRoot%\System32\dllcache.

This workaround also works if the system has Service Pack 3.

Note MalwareBytes reports this file as a trojan, but this is a false-positive and the warning may be ignored. The file is a legitimate Microsoft file, albeit from a pre-release version of a Service Pack.