Hello ​@stephaniemm77,
Custom login screens on macOS are tricky due to SIP restrictions. Most avoid disabling SIP for security reasons. Some use Jamf or Munki with DEP workflows to customize pre-login branding safely. For deeper UI changes, consider a secure post-login splash or helper app instead.

Best Regards,
Jack Cowan

This. However Jamf Pro nor Munki can change the lockscreen wallpaper. Jamf does this with Jamf Connect, which is an application that runs on top of the login window so its not technically changing the image.

​@jack567cowan Yes /understood, thats why I was asking for folks who might have used a app, I specifically said I don’t want to disable SIP. Do you have the name of “helper app” thats what I was asking for.

​@stephaniemm77 I think the helper app that they were referring to and mentioned is Jamf Connect. If you are using Jamf Connect, you can customize the login screen to display a company logo and custom background. It does this by replacing the login screen. However, if the devices are FileVault encrypted, the FV login screen after a reboot is still going to be the standard Apple login screen without the custom branding; afaik that screen cannot be change since it’s technically not a fully booted OS yet. When using something like Jamf Connect, if a user were to “logout” then they would be presented with the custom login screen that you create.