Windows 8.1 default (system) lock screen customization

ok - not sure if this is exactly what you found yourself, but have an answer for you - although its not the easiest to process:

The Sign Out screen is stored in:

C:\ProgramData\Microsoft\Windows\SystemData\S-1-5-18\ReadOnly\LockScreen_Z

You need to turn on the Show Files and Folders option from Folders Options in order to see it.

Here's how to change the sign out screen:

go to folder C:\ProgramData\Microsoft\Windows Right click on SystemData ->Properies->Security->Advanced->Change Enter your user name (You must be in Administrators group), then click on Check Names->OK Place a tick on "Replace owner on subcontainers and objects", click Apply ->OK, Yes->OK->OK->OK

Go to C:\ProgramData\Microsoft\Windows\SystemData\S-1-5-18\ReadOnly\LockScreen_Z

You will see 2 images of the Seattle Space needle in this folder, To view these 2 images.

Right click on it->Properties->Securities->Edit->Add Enter your user name, Click on Check Names->OK->OK->OK

Replace these 2 images with whatever images you want, make sure they have the same names and resolution as shown in LockScreen_Z.

IMPORTANT: After swapping the images, Right click on image->Properties->Securities->Edit Make sure SYSTEM is in the user list with permission shown below: (If SYSTEM is not in the list, you have to add it to the list using the 2 steps above)

Read&Execute Read

Sign out, you should see the new Image.

pretty straightforward this one:

1. Bring up charm-bar (lots of ways - Windows key + C - is one)
2. Click Settings
3. Change PC settings at bottom.
4. You should see image of your lock screen (the screen before you put in password) - left click on in.
5. Change screen here.

I've found an answer here. Quote:

Try this:

• Open: C:\ProgramData\Microsoft\Windows\SystemData\S-1-5-18\ReadOnly\LockScreen_Z\
• Replace the picture in there with your custom background picture. IT MUST MATCH THE NAME OF THE CURRENT BACKGROUND PICTURE (for me, it's LockScreen___1680_1050.jpg). Logoff (or restart) to see the result.
• NOTE You may have to take ownership (or grant yourself permission) to view the contents of the SystemData folder and it's subfolders.

EDIT It seems Microsoft may have released an update which the above solution no longer applies. It's still a picture in the SystemData folder, but it now has _notdimmed appended to the end of the name of the picture.

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