extra screen does not show whole desktop

Hi khansson,

Thanks for sharing the picture of what the Dock looks like, that helps to see what's happening.

Have you tried different display resolutions? If not, give that a try: Change your Mac display’s resolution

I'd also suggest going to the Dock preferences and change the Dock location from bottom to side and back to bottom. See if that places the Dock correctly.

Apple Logo > System Preferences > Dock > Position on Screen

Have you restarted the Mac and display since this started happening? That's always a good step to try, as a restart can resolve unusual issues.

Thank you!

Try using extended desktop mode instead of mirror display mode. Mirror display also mirrors the display resolution. Extended desktop mode allows you to select the native resolution of the external display.

Hi khansson,

Thanks for replying, and for the additional info, we appreciate it!

If I'm understanding correctly, the Dock is only not present on the external display when your Mac is started up in Secure Boot.

Does this happen in all three of the options that are shown in the below article?

About Secure Boot

Also, are you running any app in full screen? If so, see if going out of full screen makes a difference. Or if you need to use the pointer to the Dock's location, as shown in this article.

Use apps in full screen on Mac

Thanks!

Hey there khansson,

We appreciate you trying those additional steps, and your patience while we tried to resolve this.

What I'd suggest is to contact the display manufacturer and let them know what's happening and see if they can offer any insight.

You can also contact Apple Support for additional assistance. Also let them know what troubleshooting steps you've already done.

Thank you!

Hi khansson,

Thanks for using Apple Support Communities! I see you have an issue with an external display connected to your MacBook Pro, and I'd like to offer some assistance.

Are you using your display as an extended desktop or mirror what's on your Mac computer's screen? You can check the Arrangement at the Apple Menu () > System Preferences > Displays. Use external monitors with your Mac

If using extended desktop and the Dock is not on the screen you want it on, it will appear on any of your displays when you move your pointer to the bottom edge of your display.

If mirror is selected, then the dock should be on both screens, as they should look the same. If not, then you may need to change the display's resolution. Change your Mac display’s resolution

More info on connecting a display can be found here: Connect a display, TV, or projector to Mac

Here's some info about the Dock: Change Dock preferences on Mac

I hope this information helps you out!

Cheers!