Switching users with the Welcome Screen off - it really does work!

[Idontwantspam]

This is crazy - but true!

Somehow I got Windows XP to let me switch users, even though I have the Welcome Screen turned off and I'm using the classic logon. Totally weirdly awesome. You probably don't want to read the whole darn story; just go down to the 4th post or so to see the necessary info. If you want to read this anyway, here's how it happened:

I was making a .reg file to automate the process of making a Windows XP Logon more secure - turning off the welcome screen, turning on Ctrl-Alt-Del to logon, do not show last username, legal notice box, etc. I was testing this in a virtual machine, so that if I screwed up, my computer wouldn't be fried. So anyhow, I made a .reg file that is attached and you can see for yourself what it should do. Now I made the mistake of merging it when I had two users logged on. Administrator and Example. It was merged as Administrator. So anyhow, I pressed Ctrl-Alt-Del to test if it worked and it gave me Windows Security rather than the Task Manager, so I knew it worked. I click Task Manager and to my surprise, the User tab was still there. So I clicked on it and saw that Example was still logged on. Hmm, funny, I thought. I remembered then that I had left that account logged on. Curious, I highlighted Administrator and clicked Disconnect user. Rather than get the Computer Locked screen that I usually get, I got a login box, like the normal one. Very weird. So I entered the username Example and its password. It logged in. I did the disconnect procedure and logged back in as Administrator again. Both accounts were still on the Task Manager. So I logged them both off and logged back into Administrator and disconnected the user and logged into Example again and it still worked. After a restart, this still worked. Then I merged my "reset" .reg file, also attached. It basically reset everything back to no C-A-D, welcome screen and show username. Then I went and logged on as only Administrator, no other users logged in. Then I merged the original .reg file, and tried again. It worked.

Now the thing is Lock Computer still works. If I'm logged in as Administrator and I lock, Example can't log in. Now you're starting to get the idea of how this could come in handy. Still being able to switch users, but getting to lock the computer, and have the secure login.

So here's a few questions I have:

• What registry key, if any, controls whether user switching is allowed? SOLVED
  
• Has anyone else seen anything like this before? What do you know about this?
  
• Would anyone want to test this on their computer, and see if it works?
  
• Does anyone know a shortcut to Disconnect User? Something like using a shortcut to shutdown.exe -l to log off or rundll32.exe user32.dll LockWorkStation to lock the computer? Because this would be a much easier, useful... thing if there was a way to make shortcut to disconnect and then assign it a keyboard shortcut. SOLVED
  
• For some reason the background of the logon screen is black now. Any way to change it back to blue?
  

I'm working on a screencast of this to show what happens. It will be a flash file, either .swf or a .exe. I will upload to here if it's not too big, otherwise, I can email it to people if they want it. But it's not ready yet.

Note on the attachments:

set.reg sets the settings.

undo.reg resets those values.

WARNING: This does involve modifying your registry. I can't guarantee you won't screw something up. So don't blame me if you do.

set.reg

undo.reg

Edited May 1, 2007 by Idontwantspam

[newsposter]

heeeeeey, I wonder if this can be applied to Server 2003 to help enable more XP-like cosmetics.....

[Idontwantspam]

Not sure what you mean by that, newsposter. But it could certainly be interesting. Could you explain? I don't use server 2003...

[Idontwantspam]

OK, I resolved the issue with the disconnecting. A shortcut to tsdiscon.exe will disconnect the user, allowing a switch. If anyone can tell me where the reg data for whether FUS is enabled is, I'd appreciate it - I think that's a key part to this. I will google it when I'm done posting, but if anyone knows off the top of their head, let me know please.

EDIT:

Ah-ha! I figured it out! This is really interesting:

It all depends on the following value:

HKLM\Software\Microsoft\Windows NT\CurrentVersion\Winlogon

DWORD VALUE

AllowMultipleTSSesions

When this is set to 0, then you can't switch the users. When it is set to 1, you can switch users - even if you have the welcome screen disabled!!

So now I can switch users without having to use the (what I consider) preschooler interface, AKA the welcome screen.

I have tested this so far on only one computer, but will test it on more soon. Anyone else who can provide information would be appreciated.

I will soon create a little tutorial with some screenshots and the necessary .reg files to complete the operation.

Edited April 29, 2007 by Idontwantspam

[Idontwantspam]

The tutorial is here, though no screenshots or anything yet. You can download the ZIP with everything, including the instruction in PDF format and the reg files. Or you can read it here. The tut in the ZIP is more oriented towards people who don't know so much about the registry or Windows, so you may find it a bit obvious at times. I will put the go-change-the-registry-your-self version here for the more nerdy/geeky/whatevery people:

• Set the computer to use the Classic logon prompt, AKA the Windows 2000-style one.
  
• Open the registry. Go to

  HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\winlogon

  
  

• Find the DWORD VALUE AllowMultipleTSSessions. Set it to one.
  
• Disconnect. Either from the Task Manager or by using a shortcut to tsdiscon.exe, or a keyboard shortcut pointing there.
  
• Log in as whoever. You use it just like the normal FUS, but now you have to disconnect instead of hit Switch User. Plus, you use the secure login and you can lock the computer, etc as the Windows Security dialog comes now for Ctrl-Alt-Del, instead of the task manager.
  

I have confirmed that this on Windows XP Home Edition, XP Media Center Edition and XP Pro off of a domain. Is there anyone with XP on a domain who can report on whether this works there, too?

The attached ZIP has everything. The PDF explains it all.

fus1.zip

Edited May 1, 2007 by Idontwantspam

[DonDamm]

Thank you! This is good information. Though I don't like Fast User Switching and recommend against it, many of my customers want it or insist on it and it's good to have some info about it.

[Idontwantspam]

Yeah, personally I don't like it and I like the Welcome screen even less. On my personal laptop, I always have it disabled, but on the computer shared by the family, I have had to fight to have us use the secure Win2K style logon. Now that I can reintroduce FUS, they'll be more happy I think.