Display "no signal" after sucessful logon following wake from sleep Macbook late 2016 USBC monitor

Before you begin

You can resolve many display issues by updating the software on your Apple devices, cables, and adapters. If you can see an image on your screen, check for software updates using the Mac App Store:

1. Connect your external display and any Apple video cables or adapters that you use with it.
2. From the Apple menu, choose App Store.
3. Click the Updates button in the App Store window.
4. Install any macOS or firmware updates that are listed.

If you're using a display, hub, extender, or adapter not made by Apple, check with the manufacturer for any updates that might be available.

If you're trying to connect a 4K display or Ultra HD TV with your Mac, make sure your computer meets the requirements for using these external displays.

If the display image is blank or unusable

Try these steps if you don't see an image on your display. These steps can also help if the image on your screen repeatedly turns on and off (flickers), if horizontal lines appear (snow), or if the image is distorted (torn or scrambled).

These steps likely won't help if the issue is only happening in one app. If you see similar issues in only one window or app, check with the app's developer for updates or more help.

Check connections

Check the connections to your Mac and external displays:

• If you're using an Apple notebook, try connecting its power adapter.
• Make sure the external display's power cable is securely connected and that your display is turned on.
• If you're using a Mac Pro (Late 2013) make sure your displays are connected to the right ports.
• If you're using a display hub, switchbox, or "KVM," try connecting your display's video cable directly to your Mac instead.
• Disconnect the video cable where it plugs into your Mac, then plug it back in to reseat the connection.
• If you're using a video adapter, unplug the video adapter from your Mac, then plug it back in to reseat the connection.
• If you're using more than one video adapter to connect your display (the adapters are "chained" together), try connecting the display using only one adapter if possible. Some video adapters can't be connected together. For example, a mini DisplayPort to DVI adapter can't be connected to a DVI to HDMI adapter.
• If your display has more than one video connection, see if using another connection on the display works. If possible, check to see if using a different display or a different adapter works.
• Try using a different cable that you know is in working order. Check with the display's manufacturer to make sure you're using the cable they recommend.
• Restart the Mac with the display connected.

Start up in safe mode

To start up in safe mode:

1. Start or restart your Mac, then immediately press and hold the Shift key. The Apple logo appears on your display. If you don't see the Apple logo, learn what to do.
2. Release the Shift key when you see the login window. If your startup disk is encrypted with FileVault, you might be asked to log in twice: once to unlock the startup disk, and again to log in to the Finder.

To leave safe mode, restart your Mac without pressing any keys during startup.

If an issue doesn't happen in safe mode

If an issue doesn't happen when your Mac is started in safe mode, try restarting without pressing any keys.

• If the issue comes back, you might have incompatible login items.
• If the issue doesn't come back, it was probably caused by a cache or directory issue with your startup disk, which safe mode fixed.

Use another account for testing

If another user account is already set up on your Mac, you can simply log out of your account (Apple menu > Log Out) and log in with the other account. But the best way to test is with a newly created account:

1. Choose Apple menu () > System Preferences, then click Users & Groups.
2. Click , then enter an administrator name and password.
3. Click the Add button (+) below the list of users.
4. Complete the fields shown for a Standard or Administrator account, then click Create Account (or OK).

If you plan to test with any of the documents in your own account, make those documents available to the new account. Drag them to the Shared folder of the Users folder on your hard drive (~/Users/Shared). You can then move them to other folders after you log in as the new user.

Then log out of your account and log in with the new account:

1. Choose Apple menu > Log out.
2. At the login window, log in with the name and password of the new account. If you're also asked to sign in with an iCloud account or Apple ID, skip that step.

Now try to reproduce the issue in the new account. If you need to set up an email account or other account in order to test, you can do so.

If the issue doesn't happen in the other account

If the issue doesn't happen in the new user account, the issue is related to the settings or files in your own account.

If you need help with a specific alert or issue, search the Apple Support website for the text of the alert. If the issue happens in only one app in your account, it might be related to one of that app's settings. Check the app's documentation or support website for help.

You can remove the new user account when you're done testing. Follow the steps for creating a new account, but click the Remove button (–) instead of the Add button (+). Before removing the account, make sure that you don't need any of the files or settings you created or copied in that account.