To get Concurrent Sessions in Remote Desktop on Windows XP Service Pack 2 working, follow the steps below exactly:
- Download the termserv.zip file below and extract it somewhere. (You have to be registered to see the file)
- Reboot into Safe Mode. This is necessary to remove Windows File Protection.
- Copy the termserv.dll in the zip to %windir%\System32 and %windir%\ServicePackFiles\i386. If the second folder doesn't exist, don't copy it there. Delete termserv.dll from the dllcache folder: %windir%\system32\dllcache
- Merge the contents of Concurrent Sessions SP2.reg file into the registry.
- Make sure Fast User Switching is turned on. Go Control Panel -> User Accounts -> Change the way users log on or off and turn on Fast User Switching.
- Open up the Group Policy Editor: Start Menu > Run > 'gpedit.msc'. Navigate to Computer Configuration > Administrative Templates > Windows Components > Terminal Services. Enable 'Limit Number of Connections' and set the number of connections to 3 (or more). This enables you to have more than one person remotely logged on.
- Now reboot back into normal Windows and try out whether Concurrent Sessions in Remote Desktop works. It should!
If anything goes wrong, the termserv_sp2.dll is the original file you replaced. Just rename it to termserv.dll, reboot into safe mode and copy it back.
The termserv.dl_ file is provided in the zip is for you slipstreamers out there. Just replace that file with the corresponding file in the Windows installation disks.Source