And after 3 days of maniac troubleshooting, googling and...1 hour of Microsoft Premier Support this one it's finally solved!
Here's a quick resume of the issue and, in my case, what was happening.
After apply a GPO to change Windows background to a corporate wallpaper for all users, instead of the changing to the correct image, users got a black screen.
After 3 or 4 days of troubleshooting Microsoft gave me a nice way to quickly understand if this was a problem with our image or something else.
- Get an image that originally comes with Windows, you can find them in "C:\Windows\Web\Wallpaper\".
- Now, copy the image to the same folder and the same name you've configured your GPO setting.
- Reboot the machine
In my case, the image that was delivered was 8 bit depth instead of 24 bit depth. This caused the issue.
After converting the image to 24bit depth (with Paint.NET for example) the corporate wallpaper showed up exactly how it should!
Hope this helps people struggling with this issue!