Solution for changing Big Sur login wallpaper to custom.

There *is* a procedure in the discussion of this issue that modifies the start-up screen as well, see https://discussions.apple.com/thread/252056512?answerId=255286668022#255286668022, but you have to turn off SIP and SSV, and likely the changes void AppleCare.

emd203 wrote:

I did this - it works for the lock screen when the computer logs out but it doesn't change anything for the start-up lock screen (absolutely hideous - what were they thinking?). Hope there's someone who has a solution or at least that input like this kick start a solution for the designers of the Big Sur operating system upgrade.

See my comment, above, at https://discussions.apple.com/thread/252056512?answerId=255381017022#255381017022.

LeadMare wrote:

A kelp forest isn't a field of "distracting details." The fronds lend themselves to an impressionistic representation that would make a nice login screen, e.g., from this image (from the Farallon islands, just north of Monterrey)

Yes. One could, most certainly, create «an impressionistic representation» of a «kelp forest», but such would not, necessarily, be a reasonable «impressionistic representation» of Monterrey, per se (even according to your own choice of image).

Since it is Apple’s choice of name—even as a location—it is Apple’s choice of what «impressionistic representation» they wish to use.

In any case, the underwater canyon view, they appear to have chosen, is, arguably, far cleaner—fewer lines—than any including a «kelp forest».

If you want anything different, then the only recourse is to provide Apple direct Feedback, through their designated mechanisms, such as Product Feedback - Apple.

Mark R.Norman wrote:

Why do you have to loose system security features to disable this feature? I don't think we need to have to be made to choose between our system's security and a boot up log in screen!

If you want anything different, then the only recourse is to provide Apple direct Feedback, through their designated mechanisms, such as Product Feedback - Apple.

Well, there is a variation on pauclaude's suggestion that definitely worked for me (details at https://discussions.apple.com/thread/252056512?answerId=255286668022#255286668022) but it left my mac in a state where both SIP and SSV had to be left off, otherwise it would not boot. So if the outline pauclaude posted, or some tweak to it, would work (where csrutil is re-enabled at the end), that would definitely be of interest/value. Hopefully someone will try and let us know their outcome (and whether it persists across a couple of successful reboots, in particular).

Yes the fact that the "select user for login" screen is different from the password/lock screen, at least when there are multiple user accounts on the Mac, is well covered in the discussion on this question, and the filename of the file that controls that select user/login screen has been determined, but it is in a portion of the file system that you can't change without disabling SIP and SSV security -- see https://discussions.apple.com/thread/252056512?answerId=255286668022#255286668022 for details.

glenidol:

In your post (Oct 15, 2021 6:45 PM in response to Halliday), you claimed: «Display name and password for a single user does not show that eye boggling colour.»

You now seem to be confirming what I wrote in response to your comment, then:

«We have been seeing cases of Single User systems where, using “Display login window as: Name and password” always displays the Big Sur Graphic image («that eye boggling colour», as you put it). Yet, once changed to “Display login window as: List of Users”, that would be skipped for the Lock Screen.»

(This was why I wrote my comment, Oct 15, 2021 2:58 PM in response to EdFladung3, just above the first comment you wrote to me, on this page.)

Is this all correct?

It worked, thanks for posting these instructions.

As soon as I changed the desktop from Big Sur background to the rainbow and back I saw that the file had been created.

For Number 10, which folder do you grant permission to? For me I granted permission to both the UUID and desktop pictures folder.

A few suggestions to make your instructions clearer:

1. Go to System Preferences > Users & Groups
2. Click lock to make changes
3. Right click on user in left column > Advanced Options
4. Copy UUID value
5. Go to Macintosh HD/Library/Caches/Desktop Pictures
6. If it doesn't exist create Desktop Pictures folder
7. Inside Desktop Pictures create folder with UUID value as name
8. Right click on folder > Get Info
9. Open lock to make changes
10. Grant permission to Read & Write for user, admin and everyone for both the UUID folder and Desktop Pictures folders
11. Make sure FileVault and Guest user are deactivated
12. Change desktop wallpaper
13. Restart your computer

Big Sur will now always create a lockscreen.png file in the UUID folder matching the current wallpaper.

I think Soren is right. Just in case you need more detail, I found the following route (someone else may know of a shorter route):

1. In the upper right, click on "my subscriptions."
2. In the upper left, click on "Filter."
3. On the left, under "Recent Activity," Select "Participated." That will give you a list of the threads in which you recently posted something.
4. Find the thread you want to "unfollow" and click on the + to the right of that thread.
5. Click on the button that says "Following." That should unfollow it. If you click on it again, it should give you the option to "Follow," so you will know you have unfollowed it.

I hope that works if the button on the discussion page itself is not working for you. Again, I'm very sorry for my venting if that is the problem. I won't post any more on this thread as I'm sure it must have become annoying.

Okay. I spoke with Apple telephone support, and here is what I got on this issue:

1. At least for a MacBook Pro, there is absolutely nothing wrong with just putting your computer to sleep when you are through using it instead of turning it off. If you do that, you will not get the start up image that we don't like when you wake it the next day.
2. However, you should shut it down at least once every week or two and re-start it the same as you would shut down and restart your iPhone from time to time to give it a fresh start. If I shut it down at night once every 10 days and restart it the next day, I get that image 3 times a month until Apple has a fix and I can live with that.
3. There is currently no way to change that image that we get when we first turn on the computer. At least not yet.

Hi hildegard47, arizonanorse,

Thanks for getting the information from Apple. I don't quite agree with everything though.

1. Yes there is nothing wrong with just putting the computer to sleep but that doesn't mean one should leave it asleep for long periods. I had to out this afternoon but knew I was coming back so I closed the lid and put it to sleep.
2. I shut down my Mac every night as leaving it asleep for long periods isn't recommended even if Apple says so. What if there is a poweroutage or something happens to the power then computer will run out of battery and turn off by itself loosing whatever important you might have up.
3. One has to take what Apples says with a grain of salt sometimes. They've told me things in the past that I knew were just plain wrong. Since I have 20 years and more of Mac experience, I say thanks and try what I think and usually it solves the issue.
4. If you meant officially, then yes you are correct but there is a way to changes the login screen background following these steps. I tried it on my own Mac and it worked. For me the Desktop pictures folder didn't exist in Macintosh HD/Library/Cache/ but once created my login background is synced with my desktop background. As people have said and it's interesting, it works for some but not others. I'm aware of one having to turn off FileVault and all that.

I hope this helps and wanted to share my thoughts on the situation as well.

Thank You @applewarm !

Have you tried this out personally ?

https://www.titanium-software.fr/en/release_onyx.html

OnyX 3.9.3

• Issue corrected that deleted the widgets when running the maintenance tasks

Is this fully functional ? I wan't to use to use this to change the lock* screen.

I have 3 user accounts and unfortunately your method did not work for me although i really appreciated the effort ! =)

I must say i was impressed.

• I'm on the latest version of Big Sur 11.1 on Mac Mini M1.
• Wireless Logitech Keyboard + Mouse

I'm waiting for somebody to confirm it is 'safe' to use this method. Thank You guys.

We should not have to work so hard to change a lock screen. It's rather ridiculous.

About Me:

• I have 2 user accounts. 1 admin and 1 standard
• I disabled file-vault
• I have automatic log-in on my 'standard' account aka bypasses the login screen automatically
• I have fast-user switching 'ENABLED'*
• @Ive46 [another user] stated they tried Onyx method and it did not work so I thanked them and clicked 'helpful'
• I did not not actually try it myself as I saw no reason to if the rainbow screen still remains.
• I only actually see the screen for a very short time while 'fast switching' so its tolerable but i do see how this could this is incredibly annoying for most users otherwise we would'nt be 22 pages deep into this thread lol.

Welcome, E. Kennedy, to Apple Support Communities!

I see you have not had success with applewarm‘s suggestions.

Unfortunately, there are a few nuances that were not included in applewarm‘s original suggestions:

1. Such only work for truly Single-User systems: hence the reason for having to disable the Guest account. Multi-User systems will always see the Login Screen (always the colorful Big Sur Graphic image), prior to choosing a User (provided the system is not using the Username/Password dialogue for logins).
2. Those suggestions don’t take into account that some people have chosen to use the Username/Password dialogue for logins: this approach, even for a Single-User system, will never show the user’s Lock Screen (with the possible exception of the user explicitly putting their computer into Locked mode). One will always see the colorful Login Screen with the Username/Password dialogue for logins.

None of us have found a way to replace the background of the Login Screen: it’s always the colorful Big Sur Graphic image.

Does any of the above help you see why your system is not doing what you want?

Which Library is this? Your user Library > Caches or Macintosh HD > Library > Caches?

I assume it's Macintosh HD > Library > Caches.

That's a screenshot of Macintosh HD or in my case MacOS Big Sur > Library > Caches. it looks like I don't have the Desktop pictures folder. I wonder why one might have it and other don't?

Thanks, please clarify.