How to fix Mac that won't wake up from sleep or has a black screen after waking

Summary

This guide helps you troubleshoot and resolve: How to fix Mac that won't wake up from sleep or has a black screen after waking. Follow the steps below to fix the issue.

Common Causes

When your Mac refuses to wake from sleep or shows a black screen after waking, it can be caused by power management glitches, display issues, or software conflicts. In most cases, the problem can be resolved with a few targeted steps before needing further investigation. This guide walks you through the most effective fixes, starting with the quickest and moving to more detailed troubleshooting.

Quick Fix Steps

Try these steps in order. Many users find the issue is resolved after the first or second attempt.

1. Press a key or click the mouse. Sometimes the Mac is awake but the display hasn't refreshed. Move the mouse or tap a key on the keyboard to trigger the screen.
2. Press the Touch ID button or power button briefly. On a MacBook, tap the Touch ID/power button once. On an iMac or Mac mini, press the power button once. Do not hold it down.
3. Check the display brightness. If the screen looks completely black, try increasing brightness using the F2 key or the Brightness control in Control Centre.
4. Disconnect external displays. If you use an external monitor, unplug the cable or dock. A faulty display handshake can prevent waking.
5. Force restart the Mac. Press and hold the power button for about 10 seconds until the Mac turns off completely. Wait 5 seconds, then press the power button again to start it up.

Detailed Instructions

Reset the System Management Controller (SMC)

The SMC controls power, battery, sleep, and display behaviour on Intel-based Macs. Apple Silicon Macs manage these functions automatically and do not have an SMC reset procedure. Skip this section if your Mac uses Apple Silicon.

For MacBooks with the Apple T2 Security Chip (2018 to 2020 Intel models):

1. Shut down your Mac.
2. Press and hold Control + Option + Shift on the left side of the keyboard for 7 seconds.
3. While still holding those keys, press and hold the power button as well for another 7 seconds.
4. Release all keys, wait a few seconds, then press the power button to turn on your Mac.

For iMac, Mac mini, Mac Pro (Intel):

1. Shut down your Mac and unplug the power cable.
2. Wait 15 seconds.
3. Plug the power cable back in and wait 5 seconds.
4. Press the power button to turn on your Mac.

Reset NVRAM or PRAM (Intel Macs Only)

NVRAM stores display, sound, and other settings. Resetting it can resolve wake and display issues on Intel-based Macs.

1. Shut down your Mac.
2. Press the power button, then immediately hold Option + Command + P + R.
3. Hold the keys for about 20 seconds. On Macs that play a startup sound, you can release the keys after the second startup sound. On Macs with the Apple T2 chip, release the keys after the Apple logo appears and disappears a second time.
4. Let your Mac start up normally.

Check macOS Power and Display Settings

Incorrect power settings can prevent your Mac from waking correctly.

1. Open System Settings (or System Preferences on older macOS versions).
2. Click Battery (on a MacBook) or Energy Saver (on a desktop Mac).
3. Review the settings under Options and ensure Wake for network access is enabled if you rely on remote access.
4. Open Lock Screen settings and confirm the Start Screen Saver when inactive and Turn display off when inactive values match your expectations.

Boot into Safe Mode

Safe Mode starts macOS with only essential software and runs several background checks. It's a useful way to determine whether third-party software or login items are causing the issue.

1. Shut down your Mac.
2. Press the power button, then immediately hold the Shift key.
3. Release the Shift key when you see the login window or desktop.
4. Test whether the wake and display issues still occur.
5. Restart your Mac normally to exit Safe Mode.

If the problem does not occur in Safe Mode, a login item or background application is likely the cause. You can remove login items from System Settings → General → Login Items.

Troubleshooting

Check for macOS Updates

Apple regularly releases updates that fix sleep and display bugs.

1. Open System Settings → General → Software Update.
2. If an update is available, click Update Now or Restart Now.
3. Allow the update to complete and test your Mac afterwards.

Test with a Different Display or Cable

If you use an external monitor, the cable, adapter, or display itself may be the source of the problem.

• Try a different cable, preferably a known-good one.
• Connect directly to the Mac instead of through a dock or hub.
• Test with a different display if available.
• Check the display's input source setting.

Disconnect Peripherals

Faulty USB devices, docks, or Bluetooth accessories can interfere with sleep and wake behaviour.

1. Shut down your Mac.
2. Disconnect all non-essential peripherals, including USB drives, printers, and external displays.
3. Connect only the essentials (keyboard, mouse, power) and test whether the issue persists.
4. Reconnect devices one at a time to identify the culprit.

Run Apple Diagnostics

Apple Diagnostics can check for hardware issues that may affect sleep and display functions.

1. Disconnect all external devices except the keyboard, mouse, display, and power.
2. Shut down your Mac.
3. Press the power button, then immediately hold the D key on Apple Silicon Macs, or Option + D on Intel Macs.
4. Release the keys when you see the language option or a progress bar.
5. Follow the on-screen prompts and note any reference codes.

Check Console Logs for Clues

Console logs can reveal what happened at the time your Mac failed to wake.

1. Open the Console app from Applications → Utilities.
2. Select your Mac under Devices.
3. Search for keywords such as wake, sleep, display, or black screen around the time the issue occurred.
4. Note any repeated errors or process names and include them in your support ticket.

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