Tried putting customizing the sign in screen, now it's blank

Suggest you try reverting your changes, then follow the appropriate tutorials.

Besides manual reversion, you could
- use a System Restore point (do you have that enabled?)
and if all else failed
- restore using a disk image you've previously created (the routine and regular use of disk/partition imaging is endlessly recommended here e.g. Macrium Reflect (free/paid) ).

Hi blackkeys1098.

If you use Macrium Reflect or even just have a system restore point this is easily done (as said by dalchina) but if not sadly it's quite hard..

If the issue is only on one account (or the only account) follow these steps:
running the Deployment Image Servicing and Management. This tool will automatically repair the components of your Windows operating system and records the corruptions to the log file.

To run the DISM tool, follow these steps:

Press and search 'Command Prompt'. Then, Right-click on Command Prompt on the search results and then select Run as administrator. If you are prompted for an administrator password or for a confirmation, type the password or click Yes.

In the Command Prompt window, type:

Code:

DISM /Online /Cleanup-Image /RestoreHealth

, then hit Enter.
Once the scan is finished, restart your computer.

While running the DISM tool on your computer, if any bad sectors are found on the system, data loss might occur. I would recommend that you backup your files before running DISM.

If this doesn't work, you can try to reset Windows Spotlight:

1. Go to Settings > Personalization > Lock screen.

2. Ensure sure that Windows Spotlight is selected under the Background option.

3. On the search field on your taskbar, type Windows PowerShell.

4. Right-click Windows PowerShell, and choose Run as administrator.

5. Copy and paste the command below, and then restart your computer.

Code:

Get-AppxPackage -allusers *ContentDeliveryManager* | foreach {Add-AppxPackage "$($_.InstallLocation)\appxmanifest.xml" -DisableDevelopmentMode -register }

-James

[QUOTE=blackkeys1098;2359041]... I tried to put a custom wallpaper for the sign in screen...QUOTE]

This website provides a procedure but I have not tried it.
How to Change Your Windows 10 Login Screen and Desktop Wallpaper | Digital Trends

Best of luck,
Denis