Monterey Login Screen is Stuck on Chroma Red (different than the Pink Monterey Valley screen!)

I’ve called Support at Apple and lodged an official complaint about this. The support person said they can see this discussion and other discussions about the problem. He said there is currently no way for a user to change the login screen. If we all write to Apple and lodge a complaint it could be fixed in a future update.

Well said Ralph!

There can be different software running the login screens for Intel-based Macs and Macs with Apple silicon, if FileVault is enabled. On Intel-based Macs (AFAIK), they boot to a special login screen stored in the Preboot volume (/System/Volumes/Preboot). In contrast, Macs with Apple silicon start up from the SSV and show the real login screen, but because the Data volume is locked, they use a default background and rely on info stored in the Preboot volume (user icons, names, SecureTokens, etc.) to let the user unlock their Mac for the first time.

I'm not sure if a smaller filesize can help reduce the chance of malware infecting a file. I'd rather blame the command "diskutil apfs updatepreboot /" for not providing higher-resolution pictures. Maybe the Intel pre-boot screen can only handle a lower resolution?

It is possible to disable the SSV protections (by running "csrutil authenticated-root disabled") from macOS Recovery. This isn't a good idea (since it will put you in Permissive Security on Apple silicon Macs), but if you choose to do that, the following applies:

• When you disable SSV integrity, FileVault must be disabled. You can enable it again after the security changes have been applied.

• The system always starts up from an immutable snapshot. The only change now is that you can create your own custom system snapshots, using apfs_systemsnapshot. Also, each file is no longer verified by Apple (since you broke the seal).

• In order to create a custom snapshot, you would have to mount the live System volume (unmounted by default), make it read-write, and then perform any desired changes. (This may require disabling System Integrity Protection completely on Intel-based Macs, or at least the filesystem protections, unless you're fine with making your desired changes using Terminal in macOS Recovery.) Once that's done, a new system snapshot would have to be created in order to lock in the changes.

• On an Intel-based Mac, if you reset NVRAM, that will automatically re-enable SSV integrity, and you'll likely be stuck in a boot loop if you're using a custom snapshot. To fix this, start up from macOS Recovery and either disable SSV integrity again, or reinstall macOS (which will preserve your data, but remove any system volume customizations.)

• When the next macOS update is available, it will be much larger than normal, and it will completely rewrite the entire system volume. All of your custom snapshots will be lost, and you'll go back to the default login window wallpaper.

• In macOS Big Sur, if you start up from a custom system snapshot, the sealed snapshot will be automatically deleted. Your only remedy of going back to the SSV is to reinstall macOS, or wait for the next update (which will do the same thing).

• In macOS Monterey (and hopefully future), if you start up from a custom system snapshot, the sealed snapshot will be preserved. If you choose to revert back to the SSV though (by going to Full or Reduced Security, or running "csrutil authenticated-root enable"), your custom snapshot will be deleted.

The default desktop picture files are located in /System/Library/Desktop Pictures.

This is wrong. This thread is about the background of the login screen—the one Apple calls the "Login Window" used for switching between user accounts— not the desktop background or the background of the lock screen. If you can share an example of a login screen on a new M1 Mac running Monterey that is not Chroma Red or Chroma Blue, or better yet, if you can demonstrate how to switch away from either of these, that would be helpful.

I've had this same issue since I set up my new M1 MacBook Pro. I assumed the Chroma Red wallpaper was being cached somewhere on disk, so I tried a search for both the PNG version of the wallpaper (the one that ends up in "UUID/lockscreen.png") and the original version in "/System/Library/Desktop Pictures/Chroma Red.heic" by using the file size:

sudo find / -size 11444683c (PNG version)
sudo find / -size 41337084c (HEIC version)

Unfortunately, I couldn't find any other copies. Either it's in a directory we don't have access to as 'root', or it's in a different file format (and therefore a different size), or the system is somehow stuck looking at that original HEIC version due to some configuration file rather than a cached copy of the image.

Thank you for creating this separate thread--I got here from the one you linked above.

I really hope this gets fixed. I just got this new M1Pro MacBook Pro, and I can't believe we're already dealing with bugs. And the worst part is that this image is just so awful! Also, is there a consensus on whether this is called the 'Lock screen' or the 'Login screen?'

For further research, and if Apple happens upon this thread:

2021 14" M1Pro MacBook Pro

MacOS Monterey - 12.0.1

Filevault - on

One user

Guest User - Off

Automatic login - Off

Display login window as: List of users

Show the Sleep, Restart, and Shut Down buttons

Indeed. Received my M1 Max MacBook Pro yesterday and was surprised to see the Chroma Red login screen. Just awful. After seeing the Chroma Red, I would gladly take the Pink Monterey Valley login screen that so many also complain about. C'Mon Apple, you really need to make this user configurable ASAP!

Same issue here (MacBook Pro 16″ 2021 Silver, macOS Monterey 12.0.1).

When the boot screen ( logo & progress bar) disappears the login screen is 'Chroma Blue'.

There are 2 users I can choose between.

Once a user is selected the background of the login screen is whatever has been set as desktop background by that user.

Once logged in and whenever switching back to the login screen, the background of the login screen remains 'correct', until you decide to go back to the list of users. The background of the login screen then returns to 'Chroma Blue'.

Looks like (the ugly) 'Chrome Blue' is for the ones that opted for the silver finish and (the even uglier) 'Chroma Red' for the space grey enthusiasts.

Interesting observation regarding 'Blue' for the silver Macs and 'Red' for the grey!

I tried searching all the PLIST files on my system for any mention 'Chroma Red', but the only hit was not relevant.

I was going to try deleting the HEIC file from the Wallpapers folder to see what would happen, but deleting something from the system partition on a Mac is not easy, and I figured I might as well wait until Apple just fixes it...

I have the same issue on a 1 day old iMAC. Wife says - change that screen!!! OK . . the location is system/library/desktop pictures/monterey graphic.heic. Then it is called Monterey Graphic.HEIC and called an HEIF image. The file is locked and limited, and opening the picture information will not permit a permission change. There are 5 static pictures I think, so it must change as a true screensaver.

If you can fix the permissions, and rename it the same using a different HEIC/HEIF format, please post the results. Don't go to the user directory, that is not going to work for the common login screen background anyway. I submitted a feature request, should it be a bug?

Same issue.

Something else I noticed: the UI between an Apple Silicon Mac and an Intel Mac on this "Initial Login Screen" are actually different. On an Intel Mac running Monterey (12.2), when you select a user with the arrow key on the Initial Login Screen the user profile picture and name are highlighted by a transparent rectangle with rounded corners. On the Apple Silicon Mac the user profile picture is highlighted by a white ring. Two distinctly different UI elements for the same action. This leads me to believe that the software running for the Initial Login Screen on an Apple Silicon Mac (at least on the MBP) is actually different than that on an Intel Mac. The UI was designed to be similar, but it is not exact. Wherever this software is, be it in a hidden inaccessible volume or in some kind of read-only firmware, is where I suspect this wallpaper is.

I've been looking into this quite a bit. Turns out, this is not a bug. I'm not sure if it's all M1 Macs or just the new M1 MBPs, but I can at least now confirm that all M1 MBPs show Chroma Red/Chrome Blue by design.

A LOT has changed in macOS since the Intel Catalina/Pre-Catalina days and M1/Monterey. I did not realize that the macOS I knew is long gone. I learned quite a bit by reading through the articles here: https://eclecticlight.co/m1-macs/ The author, Howard Oakley, has done an absolutely incredible job documenting the changes that have been made to macOS in the last 4-5 years.

These wallpapers are either part of the SSV (Sealed Snapshot Volume) or part of the new iBoot on M1 Macs—I'm not sure which. In any event they are (practically speaking) unchangeable. They are part of the OS that is signed and distributed by Apple and can be (and likely are) model number specific. I say that because that's how it's been on iOS for a while, it's just less noticeable—iOS default wallpapers are different based on model.

The reason behind locking down this wallpaper is security. All parts of the system that load before login are designed to be signed and bit-for-bit unmodified by Apple. How/why Apple allows the user profile icons to load I'm not sure. If you notice, they are extremely low resolution before you login. If I had to guess what Apple is doing here is saying that user profile photos are okay to load because they are heavily compressed, so they may feel there isn't a practical way to include a malicious payload into a user profile picture that is only a few kilobytes, so it is not deemed a security risk. A high resolution desktop wallpaper, on the other hand, could be a security risk so it is not allowed; and the alliterative—compressing a desktop wallpaper to a few kilobytes would be quite ugly. How and why they decided to make it Chroma Red/Chrome Blue I have no idea, but it is what it is.

One final note: it might be technically possible to change this, but to do so you would have to turn off almost all of the security features and really dig around to find out where this screen is. You'd also have to enable Permissive Security mode and turn off SIP. The wallpaper would also be reset with any future macOS update. It may cause all sorts of other unintended problems, since system integrity will no longer be bit-for-bit verified.

I've been affected by this issue on two different laptops, and in both cases the login screen background changed to "chroma red" after restoring the laptop from a Time Machine backup. I hope this information helps Apple reproduce and fix the issue.