Changing the login screen with OS Mojave

Many threads suggest manipulating Mojave.heic, but by itself this doesn't do the trick. But, heureca, I did find a way today.

For as long as your disk isn't encrypted – and for as long as you have only one user account – the log in screen picks up whatever wallpaper you set.

However, if your disk is encrypted, you must toggle encryption for image replacements to take affect:

1. In /System⁩/⁨Library/⁨Desktop Pictures⁩/, move out or rename Mojave.heic _and_ Mojave.jpg.
2. With Preview, create a .heic file form the desired login image. Rename it as Mojave.heic and place it to its original location.
3. Turn off FileVault – and restart. You should see your current desktop wallpaper at login now (unless you've got more than one user account.)
4. Log in and turn on Filevault – and restart. You sholuld see the desired login image.

Note

• Apparently, you don't need to create a modiefied Mojave.jpg. Yet if you leave the original in its place, login will pick up that JPG copy instead of the HEIST, as if desperately searching for dunes.
• While you run on battery, the change in decryption or encryption won't be affected, just the switch is turned. This alone was suffcient in my case.

BTW, if you chose a brigtly coloured login image, you will notice artefacts around the progress bar once you're past login on the black screen after. Even the default Mojave.heic has got them if you look closely, but they stand out less because of the dark tint on that portion of the image. Hopefully someone figures this out.

Hello,

I managed to get this thing working without disabling FileVault.

What I did was:

1) Change the Mojave.heic to my custom image (copying the actual display dimension DPI).

2) Go into System Preferences > Users & Groups > Unlock the panes in the lockpad > Go to the Guest user and enable or disable.

- The point is to "refresh" the system parameters to that point.

3) Restart, change back to the Guest settings of your preference.

I don't know if this would work globally, but to me, after trying a lot of things, that worked. Seems kind of logical also :-)

Apologies, erikbock, you are right, that's the correct directory with path "/⁨Library/⁨Desktop Pictures⁩/". I have a lame excuse for this capital error of mine. What's called "Conundrum SSD" on your Mac is called "System" on mine, and the name is dutifully reported on 'Get Info' from where I copied the path.

I believe the must me a file called 'Mojave.hiec' for the system to boot. So the best is may be to duplicate it, keeping the original under a new name ('X-Mojave.hiec') while creating a new one with the desired content under the original name.

Wow, that's much easier. Trying that hadn't occurred to me. It appears that "system refresh" is trigged by equally by enabling/disabling a user account and toggling FileVault. Good to know!

In your case, did you also spot artefacts around the progress bar once you're past login on the black screen?

No, but as you mentioned, when the background is black, it's hard to spot. I have an almost all-black. I'm afraid to change to a white one to check it and later won't be able to reproduce the same results hehehe :-D

Cheers!

As you can see here there is no Desktop Pictures in /System⁩/⁨Library/⁨

It is here in just /Library/

I found the Mohave.hiec file here but am having some issues with the renaming. I will play with it some more when I have more time.

For me it was just in /Library.

Or...could Apple just make it a setting that we can change in preferences?, given that so many people are unhappy with it. Aren't Macs supposed to be plug and play?

Aren't Macs supposed to be plug and play?

Not since the beginning of the 21st century.

Straight to the point.

1. Go to MacKintosh HD>Libraries>Desktop Pictures
2. Delete pictures you don't want
3. Go to Picture folder
4. Crop picture you want as login screen background to screen res, in Apple menu and about this mac.
5. Copy and paste to Desktop Pictures
6. Rename as Mojave.heic
7. Disable Filevault and Guest login in System preferneces
8. Restart
9. Well Done

/Library is a folder in your home directory, accessible only to you. The directory I mentioned (/System⁩/⁨Library/⁨Desktop Pictures⁩/) is system wide, holding the wallpapers for all users. If you can't see it, probably the reason is that "show hard disks" may not be enabled in Finder. You can change this via Finder preferences, see screenshot.

What happened with the renaming?