Duncan Smart’s Weblog

At home, our PC running Vista is rarely rebooted and is either in a low power state sleeping or being used by either me or my wife. One thing we’ve taken great advantage since the XP days is Fast User Switching which allows someone else to log in to their desktop whilst yours is kept running in the background. My wife and I had got quite used to doing a quick WinKey+L (as you do) before relinquishing control of the PC to one another. In Windows XP WinKey+L is does a “lock workstation” which in non-domain machines takes you back to the Windows logon screen. Unfortunately on Vista it takes you to a “workstation locked” screen, so you then have another mouse click on the Switch User button (followed by monitor re-syncing itself - why does it do this? All users run at the same screen resolution) to take you to the users screen. Of course there is a “Switch User” command tucked away in the little menu next to the lock button on the start menu - but a quick keystroke is what we’re after here.

So - I go off searching for a shortcut key that does a “switch user” rather than “lock workstation”. After a 20 minutes fruitless Googling for some special key combination, I sat back, thought about it logically and came up with this solution:

1. Create a shortcut on your desktop to TSDISCON (* see below) and call it something like “Switch User”
2. Go the shortcut Properties page and assign a shortcut key. Note that unfortunately you can’t use the Windows Key in your shortcut - so I went for CTRL + ALT + SHIFT + L
3. Right click Start button and choose “Open All Users” and move the shortcut into the Programs folder (confirming the UAC prompt as you go).
4. Log out, and back in again. This is necessary because Explorer hasn’t noticed there’s now a shortcut with a new shortcut key it should be taking notice of.

And that did it. CTRL + ALT + SHIFT + L isn’t quite a neat as WinKey+L but it’s a hell of a lot better than poking around in the Start Menu.

* What is TSDISCON you ask? It’s the Terminal Services Disconnect command. Fast User Switching is all made possible by the core Terminal Services technologies which introduced the concept of multiple Window Stations or “sessions” running concurrently on the one machine. It was of course originally designed to support multiple users connecting concurrently to these sessions over the network using the Remote Desktop Protocol (RDP), but Windows XP took advantage of the multi-session architecture to enable Fast User Switching. (The RDP stuff is still there but hobbled to only allow one user to connect at a a time.)

UPDATE: If you don’t have tsdiscon.exe on your system for some reason (maybe it’s only available in Business/Ultimate or something) then you can use the following C# code (compiled into a Windows EXE using C:\Windows\Microsoft.NET\Framework\v2.0.50727\csc.exe if you don’t have Visual Studio) to do the same thing. Tsdiscon.exe is just a wrapper around WTSDisconnectSession. I used Dependency Walker (aka depends.exe) to find out what was being used:

using System;
using System.Runtime.InteropServices;
using System.ComponentModel;

class Program
{
  [DllImport("wtsapi32.dll", SetLastError = true)]
  static extern bool WTSDisconnectSession(IntPtr hServer, int sessionId, bool bWait);

  const int WTS_CURRENT_SESSION = -1;
  static readonly IntPtr WTS_CURRENT_SERVER_HANDLE = IntPtr.Zero;

  static void Main(string[] args)
  {
    if (!WTSDisconnectSession(WTS_CURRENT_SERVER_HANDLE,
         WTS_CURRENT_SESSION, false))
      throw new Win32Exception();
  }
}

UPDATE 2: For your convenience: I’ve compiled the above and packaged it into a ZIP along with the source for download here.