BluetoothUIServer bug steals focus every 30 seconds triggered by unpaired Bluetooth device

Number:rdar://FB9966159 Date Originated:2022-03-25
Status:Open Resolved:
Product:macOS Product Version:12.3
Classification:Incorrect/Unexpected Behavior Reproducible:Always
I was experiencing losing active window focus every 30 seconds which made typing and coding impossible. This was a new problem I had only experienced since the morning I started using the computer. The previous night was fine and didn’t have this issue.

Using a Python script to find which program was stealing my window focus
I narrowed down that the BluetoothUIServer was stealing focus every 30 seconds.
(Attached screenshot)

I had already tried
- unpair all bluetooth devices
- turn off and turn on bluetooth
- restart computer multiple times
Without any luck and the problem was still occurring.

I opened Console and observed that “BluetoothUIServer” was failing to load a window every time I lost window focus
-[JustWorksWindowController loadWIndow]: failed to load window nib file ‘(null)’.
(Attached screenshot)

Then subsequently I can also see “running board” setting bluetoothUIServer as the active window which is why I lose focus.

Upon further trial and error, I physically restarted all the Bluetooth devices near the laptop.

I ultimately found that after restarting my bluetooth speaker (Samsung M3 Wireless Multiroom Speaker), the problem was no longer occurring.

I suspect that the speaker was sending out a “bad” Bluetooth packet which triggered the BluetoothUIServer bug.

I’m unclear what is the intended behaviour with this scenario but I believe there’s a bug in either
- BluetoothUIServer should be displaying some sort of window that it is unable to do
- BluetoothUIServer should not be stealing focus in this scenario


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