Lock screen hangs (black screen, beach ball) on wake up

Troubleshooting Procedures: MacBook Air M3 Lock Screen Hang on Wake

There are several troubleshooting procedures that may help determine whether the above issue is related to macOS, firmware, or hardware.

The following tests should be performed in sequence, documenting the results after each test.

Test 1 — Clean Installation of macOS (Software and Hardware Isolation)

If the user suspects that the current issues originate specifically from macOS 27 (Golden Gate) or its associated firmware, a clean installation can help determine whether the problem persists independently of the existing software environment.

Apple Silicon Macs (M1, M2, M3, and later):

Use the "Erase All Content and Settings" option to erase the computer and establish a clean macOS environment.

Erase All Content and Settings on Mac

Important:

Always create a Time Machine backup before proceeding.

After completing the clean installation:

• Do not install any additional software.
• Do not restore applications, settings, or user data from a Time Machine backup.
• Configure the Mac as a new computer.
• Test using the built-in display only.
• Repeat the original sleep and wake procedure.

Run the computer in this configuration for a reasonable amount of time and in oder to test the above conclusions.

Document whether the original issue reoccurs, including the number of successful and unsuccessful wake events.

If the problem persists in a clean installation, this provides evidence that the issue is not dependent on the previous macOS installation, restored settings, or third-party software.

Test 2 — DFU Mode: Revive

If the issue persists after Test 1, the next procedure is to perform a firmware revive using another Mac.

A DFU Revive attempts to repair the firmware and recoveryOS without erasing the Mac's internal storage.

This procedure may help determine whether the issue is associated with corrupted or malfunctioning firmware.

How to revive or restore Mac firmware

After completing the revive:

1. Boot the Mac normally.
2. Repeat the original sleep and wake procedure.
3. Document whether the lock screen hang reoccurs.

If the issue persists, proceed to Test 3.

Test 3 — DFU Mode: Restore

The final procedure is to perform a DFU Restore.

Unlike a Revive, a DFU Restore erases the Mac and restores its firmware and recoveryOS.

This procedure will erase the Mac's internal storage.

Ensure that a verified backup is available before proceeding.

How to revive or restore Mac firmware

After completing the restore:

• Install macOS.
• Configure the Mac as a new computer.
• Do not restore from Time Machine.
• Do not install additional software.
• Repeat the original sleep and wake procedure.

Document whether the issue persists.

Conclusion

The results of these three tests should help narrow down the possible causes.

If the issue persists following a clean installation, a DFU Revive, and a DFU Restore, with no additional software installed, the evidence would increasingly support an underlying macOS, firmware, or hardware-level issue.

At that point, the logs documenting the sleep notification failures involving loginwindow and corebrightnessd, together with the btn_rst,btn_seq_reset reset-counter results, should be provided to Apple Engineering for further investigation.

The original reproduction steps should also be retained, as they appear to be a reliable way of triggering the failure.

One technical distinction worth retaining: a DFU Revive does not erase the Mac, whereas a DFU Restore does.

Are there any third-party menu bar items, utilities that modify brightness/color profiles (like Lunar, MonitorControl, Flux), or clamshell management tools installed? Those items can cause hanging upon wake.

First, confirm that you have sufficient free space on your internal storage. The absolute minimum is ~30-40 GB free space, and as a rule of thumb you should aim to have 15-20% of your total internal storage as free space. You can check the amount of free space you have on your Mac in a variety of ways:

• Select your internal drive then click File menu > Get Info, check Available space
• Go to System Settings > General > Storage, check the graphical display at the top of the settings pane
• In Disk Utility (in Applications > Utilities), by selecting the main container disk below the drive itself (you may need to select View menu > Show all devices to see it)
• In the System Report – hold the Option key and click the Apple menu > System Information (the top menu item), look for the name of your internal drive (Macintosh HD, unless you have renamed it as I did)

Note that on versions of macOS prior to Golden Gate, the ‘available’ space reported with the first two methods above was greater than the ‘free’ space reported by the second two methods. Apple corrected that confusion with Golden Gate, and as shown in the above screenshot, the available/free space is consistent across the different methods. For more details, see this User Tip.

Some steps to take to safely free up space:

Free up storage space on Mac - Apple Support

Optimize storage space on your Mac - Apple Support

How to free up ‘System Data’ and other st… - Apple Community

If nothing in the above reveals an obvious culprit, then appropriate troubleshooting steps are Safe Mode and creating a new user account to test. 

See if the problem is present when you boot in safe mode. That process performs some system cleanup and clears caches, and also disables 3rd party extensions that may cause problems.

Start up your Mac in safe mode - Apple Support

If that does not correct the issue, test in a new user account. A newly-created user account will have all settings at default, and if the issue does not occur in that new account then it provides guidance on what may need to be changed to correct the issue.

Add a user or group on Mac - Apple Support

Once the testing is complete, the new account can easily be deleted.

Delete a user or group on Mac – Apple Support

If you have 3rd party ‘protection’ software installed, that may be the problem. That includes:

• Cleaners (software claiming to automatically free up space)
• Optimizers (software claiming to make your Mac run faster)
• Antivirus software
• VPN software (unless provided by a school/employer to enable access to internal resources from a remote location)

Such 3rd party system ‘helpers’, ‘cleaners’ and ‘protectors’ do more harm than good. In fact, such products are completely unnecessary for macOS and the only ‘good’ (if you want to call it that) they do is to put money in the developers’ pockets. Cleaners and protectors cause compatibility issues, often after macOS updates. Commercial VPNs claim to hide your browsing activity from websites, and while that may be true those VPN providers just sell your browsing data to others. For the user, all of these types of software offer only harm…and if that is limited to harm to your bank account, then count yourself lucky. If you have installed such software, follow the developer’s instructions to completely uninstall it (note that some developers fail to provide instructions and their software installs can be pervasive, meaning the only way to truly remove it is to erase your Mac, reinstall macOS then restore your user files from a backup).

It might help to download and run EtreCheck, written by a long-time forum member. The free version is fine. Post the full report using the Additional Text button. No personal information is revealed. 

If it appears to be a genuine issue with macOS, bugs can be reported to Apple here:

Feedback - macOS - Apple

Also worth noting that both of your tests are on non-current versions of macOS. The current versions of macOS Tahoe is 26.7.2, and macOS Golden Gate is on 27.2. Based on your post you are running an older version, so the first step is to update your Mac to the current version.

See: Update macOS on Mac - Apple Support