How to Change Your Mac Lock Screen Wallpaper

If your Mac locks and shows a picture you did not expect, the setting is easy to miss: open System Settings, click Wallpaper, and choose the image there. macOS does not provide a separate Lock Screen wallpaper picker. Your wallpaper, Screen Saver choice, user account, and FileVault startup state can all affect which similar-looking screen you see.

This guide separates those screens, shows the supported native controls, and then explains how to add a video Lock Screen with Backdrop.

The quick way to change your Mac Lock Screen wallpaper

1. Open the Apple menu and choose System Settings.
2. Click Wallpaper in the sidebar. You may need to scroll.
3. Choose an Apple wallpaper, aerial, picture, colour, or photo.
4. To use your own image, scroll to Your Photos. On Tahoe 26, click Add Photo and choose the source. On Sequoia 15, use Add Photo for a Photos image or image file, and Add Folder or Album for a Finder folder or Photos album.
5. Lock your Mac from the Apple menu or press Control-Command-Q to check the result.

On macOS Tahoe 26, Wallpaper settings also contain Screen Saver and Clock Appearance controls. Sequoia 15 keeps those controls in separate System Settings panes. That version difference is why two accurate guides can appear to point to different places.

Lock Screen, login window, Screen Saver, and FileVault are not the same

These screens can appear in the same sequence and often share artwork, but they are not interchangeable. The Lock Screen, login window, and FileVault prompt can show password fields; the Screen Saver itself does not.

Apple notes that the startup login window may show a default desktop picture and then change to your chosen picture after you select your account. If the image appears after a normal lock but not immediately after a restart, your wallpaper setting may be working correctly—the first screen is simply earlier in the startup process.

Choose a still image, Dynamic Wallpaper, or aerial

In System Settings > Wallpaper, the available groups depend on your macOS version and what Apple has downloaded:

• Dynamic Wallpapers brighten and darken with the time of day or use a light or dark still appearance.
• Landscape, Cityscape, Underwater, and Earth aerials can animate as you lock or unlock the Mac. Apple can also use the selected aerial as the Screen Saver.
• Pictures and Colours are the simplest low-distraction choices.
• Your Photos accepts a single photo, an image file, a folder, or a Photos album.

If you use Spaces or more than one display, check the options beside the current wallpaper. Show on all Spaces applies one choice across spaces and displays; leave it off when you want to choose them separately.

For a lock screen, I favour an image with quiet space around the centre. The clock, account picture, and password field need to remain legible. A detailed family photo may look great on the desktop and become awkward once those controls sit over the important faces.

Change the Lock Screen clock

The path and available controls depend on your macOS version.

On macOS Tahoe 26, open System Settings > Wallpaper > Clock Appearance. You can choose:

• whether the large clock appears on the Lock Screen only or on both the Screen Saver and Lock Screen;
• the clock font;
• the font weight.

On macOS Sequoia 15, open System Settings > Lock Screen. Use Show large clock to choose whether it appears on the Screen Saver and Lock Screen, on the Lock Screen only, or never. You can also choose whether to show 24-hour time, but Apple does not document the Tahoe font and weight controls on Sequoia.

This is not the iPhone Lock Screen editor. macOS does not offer the same drag-and-drop Lock Screen layout, and Apple's current Mac documentation places widgets on the desktop or in Notification Centre, not on the Lock Screen.

Change the login picture and locked-screen message

The round account picture is independent of the wallpaper:

1. Open System Settings > Users & Groups.
2. Click the picture beside your user name, or click the information button beside the account and then its picture.
3. Choose a photo, Memoji, emoji, monogram, or camera image.

To add a short message below the login controls:

1. Open System Settings > Lock Screen.
2. Turn on Show message when locked.
3. Click Set, enter the message, and click OK.

A return email address or office help-desk number can help someone return a misplaced Mac. Avoid displaying a home address, phone number, client name, or anything else you would not want visible in a café.

The same Lock Screen pane controls how soon macOS requires the password after the Screen Saver starts or the display turns off. Wallpaper changes should never be a reason to lengthen that delay.

What macOS does not let you customise natively

Three common expectations come from iPhone guides or old Mac workarounds:

• A separate still image for the active-user Lock Screen: Apple exposes the choice through Wallpaper settings rather than a second Lock Screen image picker.
• Lock Screen widgets: Mac widgets belong on the desktop or in Notification Centre.
• A guaranteed custom FileVault preboot background: that screen appears before the signed-in user's wallpaper preferences are available.

I would also skip Terminal commands that write undocumented loginwindow preferences. They are not part of Apple's current supported wallpaper workflow, may have no effect on the FileVault screen, and can leave you troubleshooting an old tweak after the next macOS update.

How to use a video wallpaper on the Mac Lock Screen

Apple's built-in aerials animate during the lock and unlock transition, but a custom video requires a wallpaper app. Backdrop can prepare its video wallpapers for macOS Wallpaper settings and keep them animated while the Mac is locked.

As of September 2026, Backdrop requires macOS 15 or later. Its official Lock Screen guide gives this setup:

1. Open Backdrop.
2. Open the app's settings and turn on Enable Lock Screen.
3. Follow the setup instructions that appear.
4. Choose and apply a wallpaper in Backdrop.
5. If macOS opens Wallpaper settings, select the prepared Backdrop wallpaper there.
6. Wait up to five seconds for the wallpaper to be ready, then lock the Mac to test it.

Backdrop needs to keep running for the Lock Screen animation to work. Its desktop play/pause control is separate: pausing desktop playback does not necessarily stop the enabled Lock Screen animation.

Backdrop is not the only current app claiming this capability. Wallper's first-party documentation also describes native Lock Screen video on macOS 26 and later. Backdrop's useful distinction for older supported Macs is that its current requirement starts at macOS 15, alongside its community library, editor, playlists, and per-display controls.

Troubleshoot a Lock Screen wallpaper that will not update

Work through these checks in order:

1. Test a normal lock, not only a restart. Press Control-Command-Q. If that looks right, the different startup image may be the FileVault or login window.
2. Reselect the wallpaper. Open System Settings > Wallpaper and click the choice again.
3. Check the Screen Saver pairing. An idle Mac may be showing the Screen Saver rather than a still Lock Screen background.
4. Try a local JPEG or PNG. This rules out a missing Photos asset, unavailable network location, or unusual format.
5. For Backdrop, confirm Enable Lock Screen is on and the app is running. Reapply the wallpaper and wait five seconds before testing.
6. Restart the wallpaper app before restarting the Mac. This is the less disruptive way to refresh a video setup.

Do not disable FileVault, weaken the password delay, or change system-file permissions to solve an appearance problem.

Choose the simplest option that does the job

For a still photo, colour, Dynamic Wallpaper, or Apple aerial, stay in System Settings > Wallpaper. On Tahoe 26, adjust the clock through Wallpaper > Clock Appearance; on Sequoia 15, use Lock Screen > Show large clock. Keep Users & Groups for the account picture and Lock Screen for the message and security timing.

If continuous motion is the point, Backdrop adds the video workflow without pretending it can rewrite the FileVault startup screen. Test the result with a normal lock first; that one check prevents most of the confusion in this setup.

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Related guides:

• How to Set a Video as Your Wallpaper on macOS
• How to Set Dynamic Wallpapers on Mac
• 5 Best Mac Customization Apps in 2026