Custom login window file being replaced?

[mconners]

Hi Folks,

A while ago, I had created a new custom login window file, it was branding for our college and it worked flawlessly. After a number of months, I am seeing on computers around our college where the login window appearance has changed, or at least, the custom look I had, has changed. It appears, this file was replaced with default settings after an OS update. As the file is located in the /Library/Caches directory, this sounds like an ever changing directory, hence the name, Caches.

Does anyone else have a custom login window they use and have found a way to keep it locked or constant so it doesn't change over time? What did you do to resolve this?

Thanks for your feedback.

[Cornoir]

Not sure if this is what you are looking for (loginwindow background wallpaper):

Here is the process to change the login window background screen to show a custom image and for that image to not show up as blurred. The 2 processes mentioned previously are both used for this.
1 - Place you custom image in the /Library/Desktop Pictures/ folder
2 - Rename Sierra.jpg to SierraBKUP.jpg
3 - Rename your custom image to Sierra.jpg and restart. You now have a custom, but blurred login window screen.
4 - Go to /Library/Caches/ and open in Preview the com.apple.desktop.admin.png file.
5 - In Preview go to Tools -> Show Inspector. Take note of the Image size (pixels).
6 - In Preview open your original custom image. Go to Tools -> Adjust Size.
7 - Change the Width & Height (pixels) to match the Image Size from Step 5. Export the file in PNG format with the name com.apple.desktop.admin into the /Library/Caches and restart.
Viola!!

[bburdeaux]

The login window image is generated automatically whenever the wallpaper is changed. You can prevent this by locking the file after you replace it with your branded one.

[mconners]

Hello @bburdeaux I had the file locked which is a strange thing. It is then installed via a policy to our student labs. The file appears locked initially, but as the Apple engineer in an email told me, it is possible being in the caches folder, the system is able to write over or replace it. So, I was thinking, maybe there is a different location that can be used that is system wide? Perhaps in the /System folder instead of the /Library folder?

Just thinking out loud. I will continue to play around and see if I hear from Apple soon.