WakeMeUpBT

Stop a MacBook from waking up every 12 seconds while it sleeps. WakeMeUpBT turns Bluetooth off when the Mac goes to sleep and turns it back on when you open the lid.

I wrote it for my M5 Pro MacBook Pro after it lost battery overnight with the lid closed. If your Mac drains its battery in sleep and pmset -g log is full of centauri wake reasons, this is probably the same bug.

The problem

One morning my MacBook Pro (Mac17,8, macOS 27.0.1) had lost 7% overnight with the lid closed. pmset -g log showed why. The Mac had woken itself about 3,600 times in 12 hours, roughly 290 times an hour, and every wake had the same reason:

DarkWake from Deep Idle [CDN] : due to smc.sysState.Wake(0x70070000) wifibt SMC.OutboxNotEmpty centauri-beta/ Using BATT (Charge:65%) 5 secs

A DarkWake is a wake with the screen off. Each one lasted 3 to 8 seconds, then the Mac went back to sleep for about 5 seconds, then the next wake came. So the Mac was awake about half the night. wifibt and centauri point at the combined Wi-Fi and Bluetooth chip.

I am not the only one. Other people see the same log lines on M5 Pro MacBook Pros, some with 20 to 30% drain per night. See the references. Apple has not commented on it, as far as I can find.

Turning Bluetooth off and on in Control Center stops the loop. It came back for me after a while, and I did not want to do that by hand every evening. So WakeMeUpBT does it.

Do you have this bug?

Close the lid for two minutes, open it, and run:

pmset -g log | grep DarkWake | tail -20

If you see a centauri-alpha or centauri-beta DarkWake every 10 to 15 seconds, you have it. To count all of them in the log:

pmset -g log | grep -c centauri

What WakeMeUpBT does

• Just before the Mac sleeps, it turns Bluetooth off. It gets the IOKit sleep notification and switches Bluetooth off before it lets the sleep continue.
• When the screen wakes, it turns Bluetooth back on. A DarkWake does not wake the screen, so Bluetooth stays off for the whole night.
• It only turns Bluetooth on if WakeMeUpBT turned it off. If you had Bluetooth off yourself, it stays off.
• It writes a small file when it turns Bluetooth off, ~/Library/Application Support/wakemeupbt/bluetooth-off. If WakeMeUpBT restarts or the Mac reboots, it reads that file and still turns Bluetooth back on.

In my test, the Mac woke every 12 seconds without WakeMeUpBT. With WakeMeUpBT, it woke one to three times in the first minute and then slept until I opened the lid.

It is one Swift file of about 85 lines, with no dependencies. A LaunchAgent starts it at login.

Requirements

• A Mac. I tested it only on my MacBook Pro Mac17,8 (M5 Pro) with macOS 27.0.1. The code does not depend on the chip, and the Bluetooth function it uses is the same one blueutil uses on Intel and Apple Silicon Macs. So it should work on other Macs too.
• It only helps if Bluetooth causes the wakes. Check with pmset -g log | grep DarkWake first. On M5 Macs the wake reason says centauri, on other Macs look for wifibt or bluetooth. If you try WakeMeUpBT on another model, please open an issue and tell me if it worked.
• The Xcode Command Line Tools for swiftc. Run xcode-select --install if you do not have them. You need them for both install methods, because Homebrew builds WakeMeUpBT from source.

Install

With Homebrew:

brew install elmarbeckmann/tap/wakemeupbt
brew services start wakemeupbt

macOS may ask you to allow Bluetooth access for WakeMeUpBT the first time it runs.

From source

git clone https://github.com/elmarbeckmann/WakeMeUpBT.git
cd WakeMeUpBT
make install

make install builds the binary, copies it to ~/.local/bin/wakemeupbt, writes the LaunchAgent to ~/Library/LaunchAgents/dev.elmar.wakemeupbt.plist and starts it.

You can delete the clone folder after the install. To put the binary somewhere else, run make install PREFIX=/some/path. It then goes to /some/path/bin/wakemeupbt.

Use one of the two methods, not both, because two copies would both switch Bluetooth.

Check that it works

With Homebrew, the log is at $(brew --prefix)/var/log/wakemeupbt.log:

tail "$(brew --prefix)/var/log/wakemeupbt.log"

With the install from source, it is at ~/Library/Logs/wakemeupbt.log:

tail ~/Library/Logs/wakemeupbt.log

After you close and open the lid, the log shows lines like these. The times are in your local time.

2026-11-02T08:48:46+01:00 started, bluetooth power = 1
2026-11-02T08:49:45+01:00 sleep: bluetooth off
2026-11-02T08:51:02+01:00 wake: bluetooth on

The next morning, pmset -g log | grep -c centauri should grow by a few per hour, not by hundreds.

Turn it off

With Homebrew, to stop it and keep it from starting at the next login:

brew services stop wakemeupbt

Run brew services start wakemeupbt to turn it on again. To remove it completely:

brew services stop wakemeupbt && brew uninstall wakemeupbt

With the install from source, to stop it and keep it from starting at the next login:

launchctl disable gui/$(id -u)/dev.elmar.wakemeupbt
launchctl bootout gui/$(id -u)/dev.elmar.wakemeupbt

Run make install to turn it on again.

To remove it completely:

make uninstall

This also removes the binary and the state file. The log stays in ~/Library/Logs/wakemeupbt.log.

Limitations

• WakeMeUpBT uses a private Apple function to switch Bluetooth, IOBluetoothPreferenceSetControllerPowerState. blueutil uses the same one. A macOS update can remove it. If that happens, the log says IOBluetooth power functions not found.
• A Bluetooth keyboard or mouse cannot wake the Mac while it sleeps, because Bluetooth is off.
• It does not fix the bug in macOS. It only avoids it. When Apple fixes the bug, you do not need WakeMeUpBT anymore.

Other ways to fix it

• Turn Bluetooth off and on in Control Center when it happens. This is enough if the loop does not come back for you.
• sleepwatcher with blueutil. Both are on Homebrew. sleepwatcher runs a script when the Mac sleeps and wakes, and blueutil switches Bluetooth. This is the classic way to do it and does the same as WakeMeUpBT.
• BluetoothGuardian turns Bluetooth off when the screen turns off. It is written in Go and needs blueutil.

I wanted a single small program without dependencies, so I built my own.

References

Reports of the same bug:

• MacBook Pro M5 Pro: DarkWake causing overnight battery drain, Apple Community
• Centauri-Alpha prevents sleep, MacRumors Forums
• MacBook Air M4 - Battery Drain During Sleep, Apple Developer Forums. Same wifibt SMC.OutboxNotEmpty wake reason on an M4 MacBook Air.

Apple documentation for the APIs WakeMeUpBT uses:

• Technical Q&A QA1340: Registering and unregistering for sleep and wake notifications
• NSWorkspace.screensDidWakeNotification

Credits

I made WakeMeUpBT with help from Claude. Claude helped me read the power log, find the other reports and write the code. I tested it on my own MacBook.

License

MIT. See LICENSE.