I broke my logon screen, can't get into Windows.

[soldier9599]

I tried to edit my login screen by altering C:\Windows\System32\authui.dll. Now all I get after the Windows loading screen is a black screen with only a white mouse cursor that I can move around.

Windows would not let me replace the file--even after I took ownership of it and altered the permissions--because it was in use by explorer. Knowing I could very well run into some kind of issue, I made a backup of the original file, saving it with a new name in System32. I used resource hacker to save a new edited version to my desktop. The only change I made was that I altered the length and width of the user image from 190rp to 0rp in order to disable it.

I figured I could not make any more progress in Windows easily, so I booted into Debian and replaced the file with my new edited version. I tried booting into Windows and faced this problem of an invisible login screen. I booted back into Debian and got rid of my edited version of the file and renamed the backup to authui.dll. Naturally, I expected everything to go back to normal. However, this seems to have made no improvement and I continue to see this black screen. Booting into safe mode results in the same problem. I do still have my Windows install disk. Unfortunately, my DVD drive no longer functions so I cannot boot using DVD drives. I don't see any easy way to run a Windows installation repair.

Any idea why this is happening or how to resolve it?

 

[Brink]

Hello Soldier,

If you have a bootable Windows 7 USB flash drive, then you could see if running a SFC scan at boot using Method Two in the tutorial below may be able to help.

http://www.sevenforums.com/tutorials/139810-sfc-scannow-run-command-prompt-boot.html

If you like, you could also do a system restore at boot using a restore point dated before this happened to undo and fix this.

Hope this helps for now,
Shawn

 

[mdnchauhan]

Hi,
How did you edit that dll. I mean which tool did you use to edit it?

 

[soldier9599]

Thanks Shawn. I guess it's about time for me to get a new flash drive anyway. I'll come back with results once I get it working or try everything.

mdnchauhan, I used resource hacker.

I just can't figure out why going to backup didn't fix it. Before doing all this I searched Everything and saw many other files called authui.dll. One thought I have is that others of those got overwritten as a result of my changes and somehow didn't change back when I reverted to backup. Could that be a possibility?

 

[soldier9599]

I got the USB stick working and tried to repair Windows. On the first try, the installer automatically detected problems and tried to repair and reboot. Didn't work. On the second try, I manually went in and told it to do startup repair. It attempted one repair and I had the same problem upon reboot. Next I tried to do a system restore, but the restore failed because it could not recover an avi file that I deleted because I watched it already. I tried this with two different restore points and had the same problem. I still can't get past this black screen and login. Is there some way to force it to do the system restore and ignore the error for this avi file?

 

[Brink]

Are you trying a system restore at boot?

 

[soldier9599]

I am doing it right away in the Windows installer ("Repair your computer" option) after booting from the Windows installer USB drive.

 

[Brink]

In that case it may be time to bite the bullet and either refresh or reset Windows.

 

[soldier9599]

I got my original Windows installation to work. It didn't take any special magic or clever tricks, rather I just tried something that probably should have been obvious to me but I missed it. Like I said I made a backup of the original file, but I actually had two. I made one while in Windows on my desktop--this was a copy. I also made a copy in the System32 directory while I was in Debian and renamed the original file to authui.dll.bak. I edited the copy and tried to boot using it rather than editing the original file, and this may be why my edit didn't work. When I tried to revert back, I used the copy backup on my desktop rather than simply renaming what was the original file, so again I couldn't get into Windows. Now I finally tried just renaming the original to its original name and getting rid of the copies, and everything booted fine.

Maybe if I actually edit the original file rather than trying to boot with an edited copy my alteration will work. All I was trying to do was get rid of the user account picture from the logon screen and I'm pretty sure I know how to do it. I'll keep trying to get my edit to work, but first I will make a tiny partition with a fresh Windows installation and test it on that. I don't want this headache again.

 

[Brink]

The original file would be best. If that doesn't help, the running a sfc /scannow command to repair system files should help fix the file.