How to Change Your Mac Lock Screen

Before we start

Personalizing your Mac to your own needs and requirements can make it much more enjoyable to use. But what if you need to do something more complicated than changing your screen login? You'll probably need some extra help, and we know where you can get it.

The powerful MacKeeper app is able to clean and secure your Mac with little effort. However, one of its best features is the professional tech support who are available 24/7. They can help you deal with more complex customization tasks and almost any other tech issues you may encounter. Download and try yourself!

Now let's get back to your Mac’s login screen. By default, it's a blurry version of your wallpaper. Luckily, there is an easy solution to unblur or change it and that’s what we will go through in this article.

But first, there are a couple of things you need to consider before attempting to change your login background on Mac:

• The photo must be in .png or .heic file format depending on your macOS version
• The photo should fit the resolution of your screen, otherwise, you’ll see tons of pixels

Below, we will share a few tricks to make sure your photo won’t get blurry. Here’s what we will discuss:

1. How to resize your image to fit Mac login screen
2. How to add your own wallpaper on a Mac
3. How to change lock screen on macOS Sierra
4. How to change login background on macOS Mojave
5. How to change screen photo on macOS Catalina
6. How to change user icons on a Mac

How to resize your picture to fit Mac login screen

1. Click the Apple logo in the top left corner of your screen and select About this Mac

2. Open the Display tab and write down your Mac’s screen resolution

3. Open the picture you want to resize using the Preview app

4. Click Tools from the top panel and select Adjust Size

5. Edit the resolution of your photo according to your Mac’s screen size determined in step 2, then click OK

6. Click File from the top panel and select Save

If you want to use a photo from your iPhone, our article on how to import photos from iPhone to a Mac is also worth checking out.

How to add your own lock screen wallpaper

1. Ctrl + Click on your desired login screen photo, select Open With, and choose Preview app

2. In the top toolbar, click the File tab and choose Save As

3. Choose PNG as the necessary file format and name it com.apple.desktop.admin.png

4. Save it somewhere on your Mac

5. Use the Command (⌘) + Shift + G keyboard combination to activate the Go To Folder menu

6. Copy and Paste /Library/Caches in the address bar, then click Go

7. Copy the new picture you saved as “com.apple.desktop.admin.png” and paste it to the /Library/Caches folder

You can use the Command (⌘) + C key combination to copy and the Command (⌘) + V combination to paste or just drag and drop the picture. 

8. That’s it! Log out from your Mac and enjoy your new login background picture

You’ll also see the image you chose whenever you turn on or reboot your Mac. In case you ever experience troubles with that, it is best to know what to do if your Mac won't shut down.

How to change the lock screen on macOS Sierra

If you have macOS Sierra, changing your lock screen photo can be much easier. All you need to do is:

1. Open System Preferences
2. Select Desktop & Screen Saver
3. Use the left window panel to choose the photo you want to use as your new background

How to change login background on macOS Mojave

For macOS Mojave, you can change the login background screen by doing the following:

1. Ctrl + Click your desired login screen photo, select Open With, and choose Preview app
2. In the top toolbar, click the File tab and choose Save As
3. Choose HEIC as the necessary file format and name it Mojave.heic
4. Save it somewhere on your Mac
5. Open Finder and go to /Library/Desktop Pictures/
6. Paste your desired login background (you can also drag and drop)
7. Your Mac will ask for your admin password to confirm the operation so you need to insert your user password
8. Congratulations! Now you can enjoy your customized lock and login screen

How do I change my lock screen on macOS Catalina?

Changing the lock screen on macOS Catalina can easily be done in just a few steps:

1. Convert your image to JPG
2. Rename your image as Catalina and save it in the Downloads folder
3. Reboot your Mac and hold Command (⌘) + R to get into recovery mode
4. From the top menu click Utilities and open the Terminal window
5. Type cp /Volumes/MacHD\ -\ Data/Users/[your user name]/Downloads/[Catalina].jpg /Volumes/MacHD/System/Library/Desktop\ Pictures/Catalina.heic
6. Restart your Mac
7. Invalidate the cached image by changing any option in Preferences > Users & Groups > Login Options
8. Now you are all set up, enjoy your new lock screen.

How to add a message to the login screen

You might be wondering why would you ever need something like that? Well, this is a good way to add a pinch of personalization to your Mac. Also, if your Mac ever gets lost (hopefully, this will never happen to you), a locked screen message is a good way to add some contact information.

You can add a message to the login screen by following these easy steps:

1. Go to System Preferences

2. Open Security & Privacy

3. In the General tab check the box next to Show a message when screen is locked

4. Next, click on Set lock message…

5. Write your message. You can add your phone number or email address to the notice. You may want to even offer a cash reward for returning your Mac

6. Voila! Now your message will appear whenever the screen is locked

How to change user icons on a Mac

You can also change the default stock icons that apple chose for you by doing the following:

1. Open System Preferences

2. Click the User & Groups icon

3. Hover over your user icon and click Edit

4. Choose your new image or just take a new photo using you Mac’s cam

5. Click Done to save the changes

FAQ

1. Why can’t I change my lock screen wallpaper?

If you’ve done everything exactly as described in the guide, you should face no problem. However, make sure you did the following:

• You converted the file format of the photo to .png or .heic depending on your macOS edition
• You resized your image according to the dimensions of your Mac’s screen

2. How do I default my lock screen?

1. Open System Preferences
2. Click Desktop & Screen Saver
3. Make sure you are in the Desktop tab
4. At the bottom of the panel, you may find a Change picture option and all you need to do is to uncheck the box next to it
5. Congratulations! You’ve successfully managed to default your lock screen

That’s it! As promised, we have provided you with all the information you need in order to change your login background on Mac.