Solution for changing Big Sur login wallpaper to custom.

Hey Applewarm ... good post. It lead me to wonder if this ugly orange lock screen thing was related to the boot loader not knowing which lockscreen.png to show since there are multiple users. In my case, I'm the only user and don't need the Guest login. I set my desktop image to the nice Big Sur picture ... awesome in Dark Mode BTW ... then disabled the Guest login. When I log out, I have the Big Sur picture as the background on the lock screen. Easy peasy!

Now, if you really need multiple users, then your process is right on. Of course that means everyone will see the same lock screen background, but that's not so bad.

Yes it's Macintosh HD > Library > Caches. For my setup, I too had to create the two folders. You mentioned that you put the png in the UUID folder? For me it was created automatically after granting permissions to both the Desktop Pictures folder and UUID folder to read write and switching the desktop background to the rainbow and back to the Big Sur one via system Preferences > Desktop & Screensaver.

For me, I just had to reboot and bam it showed the correct picture.

Hi there,

First, there is a bunch of information that is not directly useful and you could have spaced it out better so it is easier for me to read. Anyway, see below:

Apple had it working in the beta of Big Sur as it worked for me. After upgrading to beta 6 I think the desktop stopped syncing.

I followed the above steps and it worked for me. I tweaked them so it 's easier for follow and clarified a few things as well:

Go to System Preferences > Users & Groups

Click lock to make changes

Right click on user in left column > Advanced Options

Copy UUID value

Go to Macintosh HD/Library/Caches/Desktop Pictures

If it doesn't exist create Desktop Pictures folder

Inside Desktop Pictures create folder with UUID value as name

Right click on folder > Get Info

Open lock to make changes

Grant permission to Read & Write for user, admin and everyone for both the UUID folder and Desktop Pictures folder.

Make sure FileVault and Guest user are deactivated

Change desktop wallpaper to something else and then change it back

Restart your computer

For me, in order for the file to be created I went into System Preferences > Desktop and Screensaver and switch the background to something else, the rainbow for example and the back to the Big Sur desktop and the file was created automatically in the UUID folder.

I hope this helps.

No, it doesn't. I'm not going to turn off vault to do it, especially when I'm also reading that it won't work anyway with multiple users. I read the initial post, and my post was not asking someone to repeat the steps I had already read. And I don't think anyone here deserves to be insulted except Apple, so I don't think it was appropriate for you to criticize my post as "front-loaded with information." My post was front-loaded with a question: Why did Apple do this? And your post did not answer that question. It just insulted my writing for no reason. I've been a loyal Mac buyer since I had a Power Mac G4, even when I had to use Parallels because my office used Word Perfect, and Word Perfect didn't have a Mac application yet. I've gone through computers that had to be virtually rebuilt because of defective hardware and all sorts of things and have stuck with Apple. But I'm unhappy enough with this to be tempted to recycle a 2-½ year old $2000 computer and buy a PC. And a lengthy procedure that won't work for me to solve only one of several problems with this OS won't help at all. That is not what I asked for at any point in my post. But thanks for playing.

It’s not about trying «to prevent users from customising the login wallpaper», applewarm.

It’s about trying to make the System as “bulletproof” as possible—even from the users themselves. (Even as it is, we get many users, here on the Apple Support Communities, asking for help from damage they did to their own systems.)

It’s one of the primary reasons to give Apple direct Feedback, through their provided mechanisms, applewarm: Apple is neither omniscient nor clairvoyant; they can only guess at what their users want, unless the users tell them.

(Complaining here accomplishes nothing constructive.)

Actually, Soren Pearson—other than for Catalina, prior to the last Supplemental Update—macOS has always set the “login” screen (actually, the lockscreen: the screen one sees as one actually logs in) to be the same as the user’s desktop image.

When running as a Single User setup, the lockscreen is shown as the “login” screen, since there are no other users that may wish to login.

The only time the actual “login” screen was ever shown—except for Catalina, prior to the last Supplemental Update—was when the Mac was setup as a multi-user system; which, incidentally, includes simply having the Guest account activated.

I, certainly, would like to be able to have an Administrator be able to setup the “login” screen for multi-user systems, like mine.

Yes, you are correct, only the individual users login screen and desktop. The difficulty with this thread is in the definition of login screen

if you have multiple users and boot, the first screen is a select user screen with its own fixed picture. Once a user is selected then the “login screen” for THAT user appears. This is what this procedure is changing. The clue is when the procedure tells you to select a user. Also this appears to be a round about way of doing it. From settings for Display you can navigate to the individual users desktop picture and change it to anything. The “login screen” will follow it. No complications just a

user selection !!

if anyone has changed the picture behind the “user selection” screen I’d be real interested to understand how. Thanks