MacOS – Turn off Touch bar Preview on display

The new shortcut is Command-Dim Brightness. It even makes sense in the following way:

Assuming that you take advantage of the touch bar, and it displays the system controls instead of the function keys then the hand gesture is exactly the same as before when you would have pressed Command-F1 since the Dim Brightness button is where F1 would be:

The annoying thing is that if you have an application-aware touch bar configuration, then you have to bring up the system controls touch bar configuration first.

This is why, in some cases, the Display Menu (in the App Store) which adds a status item in your menu bar (and includes a Mirror Screen choice) is a good option.

The first things I would do are resetting your NVRAM followed by resetting your SMC. If resetting these doesn't resolve it, run Apple Diagnostics.

Before doing any of the following, ensure your MBP isn't connected to any external devices (e.g. display, external hard drive, etc).

Resetting the NVRAM on Late-2016 MacBook Pro models

To reset the NVRAM on all Late-2016 MacBook Pro models (with and without Touch Bar) follow these steps:

1. Shut down your machine. Yes, a full shut down, not just logging out.
2. Press the power button and then immediately press the commandoptionpr keys.
3. Keep these keys pressed down for at least 20 seconds!
4. Let go of the keys and let your Mac reboot normally.

Note 1: When you log back in you may need to readjust some of your system preferences (e.g. speaker volume, screen resolution, startup disk selection, time zone information, etc).

Reset the SMC

Your MacBook Pro has a system management controller that can easily be reset. To do this on your particular model, follow these steps:

1. Shut down your computer
2. Keep the power cable plugged in.
3. Press at the same time shiftoptioncontrol (on the left side of the built-in keyboard) and the power button
4. Let go
5. Turn your computer back on with the power button.

If this doesn't resolve the issue, use Apple Diagnostics to test your hardware.

Run Apple Diagnostics

Follow the steps below to run Apple Diagnostics:

1. Fully shut down your Mac
2. Restart your Mac
3. Immediately press the D key and keep it down until you see the Diagnostics screen appear
4. Wait for Diagnostics to finish (this typically only takes a few minutes)
5. Once complete, one of two things will appear on the screen:
   • a No issues found message
   • a brief description of any errors found plus further instructions
6. If the diagnostics test does find errors, take a note of what they are

Note: If pressing and holding the D key at Step 3 doesn't work, start again at Step 1 and, at Step 3 press and hold both the OptionD keys instead. This will try and run diagnostics from the internet instead, so you will need to allow more time for it to complete.