Move window to left/right side of screen

I had the same issue. The name of the command changed to just "Left" and "Right", if you're wanting to do custom keyboard shortcuts.

They added default keyboard shortcuts for this window tiling behavior, documented here: Mac window tiling icons & keyboard shortcuts - Apple Support

Although I will add that the "Left" and "Right" default keyboard shortcuts haven't worked for me. Fn-Control-Left and Fn-Control-Right put the scrollbar at the top and bottom, and I haven't been able to determine why. The default for full-screen, Fn-Control-F, does work for me. I work around it by adding a custom keyboard shortcut for Control-Option-Left and -Right to the commands named "Left" and "Right".

Shift-Fn-Control-Left and -Right are a similar but slightly different behavior, and the default shortcuts work for me. I imagine there must be another keyboard shortcut for scrolling that I could find and disable, but I don't know.

Hello, great question lets see what we can do!

1. Open System Settings: Click on the apple menu and select System Settings
2. Go to Keyboard > Keyboard Shortcuts
3. Select App Shortcuts from the sidebar
4. Click the + button to create a new shortcut
5. Select All Applications, or specific app if desired
6. For left side, try using "Move Window to Left Side of the Screen." For right "Move Window to Right Side of the Screen." Make sure the text matches
7. Set your desired key combinations
8. Click Add to save your changes

This should work let me know if you need help!

Mac keyboard shortcuts - Apple Support

No problem. Let's reslolve this

1. Double-Check the Shortcut Phrasing

Apple loves updating things up with every update for most up to date and seamless experience, so the first thing to check is if they’ve tweaked the command for your window shortcut.

• Head over to System Settings > Keyboard > Keyboard Shortcuts.
• Scroll to App Shortcuts and see if the command you’re using—like "Move Window to Left Side of Screen"—has been slightly changed. It might now be something simpler, like "Move Window Left."
• If you spot any changes, go ahead and edit your shortcut to match the new phrasing.

2. Update or Recreate the Shortcut

If you find out the command has changed, don’t worry—it’s a quick fix.

• Open System Settings > Keyboard > Keyboard Shortcuts.
• In the App Shortcuts section, click the little "+" to add a new one.
• Enter the exact wording for the new command (like "Move Window Left" if that’s what it is now).
• Then, assign your preferred key combo, like Control + Command + H.
• Hit save, and you’re good to go! Try using it to see if it works now.

3. Turn On Full Keyboard Access

Sometimes, macOS updates limit how shortcuts interact with the system, so you’ll want to make sure Full Keyboard Access is enabled.

• Go to System Settings > Accessibility > Keyboard.
• Check if Full Keyboard Access is on—if it’s not, toggle it on. This will ensure your keyboard can control all the interface elements, which might just solve your shortcut problem!

4. Create a Custom Shortcut Using AppleScript

Still no luck? If macOS’s built-in shortcuts aren’t cooperating, you can create your own custom window-moving script with AppleScript and link it to a keyboard shortcut.

Step 4a: Write the AppleScript

• Open Script Editor (you can find it in Applications > Utilities).
• Copy and paste this script to move a window to the left side:

tell application "System Events"
   set the bounds of the first window of (first application process whose frontmost is true) to {0, 0, (screen width)/2, screen height}
end tell

• Save the script as an application.

Step 4b: Link the Script to a Keyboard Shortcut

• Go to System Settings > Keyboard > Keyboard Shortcuts > App Shortcuts.
• Click the "+" button, choose All Applications, and give your script a name.
• Assign a shortcut like Control + Command + H to run your AppleScript.

5. Look for Shortcut Conflicts

Sometimes the problem isn’t your shortcut—it’s another one that’s stealing the spotlight! If your chosen key combo is already being used somewhere else, that can cause a clash.

• Go back to System Settings > Keyboard > Keyboard Shortcuts and scroll through the list.
• If another shortcut is using Control + Command + H, you’ll need to either disable it or choose a different key combo for your window-moving shortcut.

6. Try a Third-Party Window Manager (Optional)

If macOS shortcuts are still giving you a hard time, you might want to explore third-party apps that handle window management better. Tools like BetterTouchTool, Magnet, or Rectangle can give you more control over window placement, and they’re super customizable.

• For example, you can download Rectangle, set up your own shortcuts in its preferences, and never worry about macOS's quirks again!

7. Restart System Preferences

Sometimes, all you need is a quick refresh. Restarting the system settings might help if your shortcuts aren’t registering properly.

• Open Terminal and type the following command to restart the UI:

killall SystemUIServer

This will reset the system preferences without needing a full reboot.

8. Update macOS Sequoia

Last but not least, make sure your macOS is up to date. Apple often releases updates that fix annoying bugs like this.

• Go to System Settings > General > Software Update and check if there’s a newer version of Sequoia available. If so, go ahead and update—you might find that your shortcut issues disappear afterward!

Quick Recap

If your window-moving shortcuts aren’t behaving, here’s what to do:

• Check the phrasing of the command—Apple might have tweaked it.
• Update or recreate the shortcut if needed.
• Turn on Full Keyboard Access to give the keyboard control over all system elements.
• Try a custom AppleScript if the native shortcuts aren’t working.
• Watch out for conflicting shortcuts that might be causing trouble.
• If all else fails, consider using a third-party window management tool like Rectangle for more reliable control.

And don’t forget to update macOS—a software update might just solve everything in one go!

I had experienced the exact same issue and found this solution

"To move and resize a window to the left side of the screen on a Mac running macOS Sequoia, the keyboard shortcut is Fn + Control + Left Arrow. 

Explanation:

• Fn: Function key
• Control: Control key
• Left Arrow: Arrow key pointing left 

>The name of the command changed to just "Left" and "Right", if you're wanting to do custom keyboard shortcuts.

This solved my issue. Like the OP, I assigned my custom shortcut with "Move Window to Left Side of Screen" and "Move Window to Right Side of Screen". It stopped working when I updated my macbook pro to Sequoia 15.1. I changed the shortcut menu to "Left" and "Right". Now it's working.

This might be, moving an Application the Screen to left or right is now Built into macOS 15 Sequoia

Mouse over the Green Button of the application.

For an illustration using Safari

refer below

Similarly, you can use "Fill" to maximize/fill the screen with your window