Upgraded to Monterey, migrated to new laptop: Bluetooth won't connect to receiver

[clivechafer]

I just migrated to a new-to-me MacBook Air 2017 running Monterey. I went to connect to a Denon RCD-M41 receiver which had been connected by Bluetooth before, and there were no devices listed. I opened Bluetooth Preferences and there was a spinning wheel by Devices. I re-paired with the Denon and it showed up in the Preferences pane. I connected and the MacBook Air showed up on the Denon display. but when I went to play music it came out of my laptop speakers. I've tried everything I can find: shutting down both devices, restarting, re-pairing again, removing Bluetooth PLISTs from Preferences folder, etc. Nothing works. I did however manage to connect a pair of Bluetooth headphones to my MacBook which had not been connected before. Apparently Bluetooth problems often show up when upgrading OS... Any suggestions what to try? There's nothing from Denon on their website.

 

[newbutter]

There's something else you could try: under the Sound section in System Preferences, check if your Denon receiver is selected as the output device. Sometimes, even though a device is connected via Bluetooth, the system doesn't automatically switch the output.

Also, try resetting the Bluetooth module (Shift+Option and click on Bluetooth icon in the menu bar > Debug > Reset the Bluetooth module).

 

[IWT]

under the Sound section in System Preferences, check if your Denon receiver is selected as the output device

Excellent suggestion. Often the cause, as you suggested.

Ian

 

[clivechafer]

There's something else you could try: under the Sound section in System Preferences, check if your Denon receiver is selected as the output device. Sometimes, even though a device is connected via Bluetooth, the system doesn't automatically switch the output.

Also, try resetting the Bluetooth module (Shift+Option and click on Bluetooth icon in the menu bar > Debug > Reset the Bluetooth module).

Things have got weirder. I eventually found that if I went to the radio mast icon top right in Music and clicked on the Denon there the music stopped playing from my internal speakers. But I couldn't hear it come out of my Denon's speakers. However, if I stood right in front of them, I could just faintly hear my music. So I turned up the volume to max on both the Denon and the MacBook and it was just about comfortably audible - but obviously not sustainable: it would have blown the circuits in the receiver to have it on max all the time, and if I changed to another source without lowering the volume it would blow the speakers.

This morning I went back in and found:
a) the two devices (receiver and headphones) I had paired last night were no linger listed when I click on the Bluetooth symbol in the menu bar. Nor are they listed in Bluetooth Preferences.
b) Bluetooth is on when I click on the menu bar symbol, but off in Preferences. When I click Bluetooth on there, nothing happens.
c) When I clicked on the radio mast symbol in Music the Denon was still there, but when I clicked on it it disappeared, and now the radio mast symbol has also disappeared on the Music page.
d) When I shift-option-click on the menu bar Bluetooth symbol it says Discoverable: off. No idea why, or how to turn it back on.
e) I tried re-pairing the receiver again, but it no longer shows up in Bluetooth Preferences when I have Pairing flashing on the receiver.
So it seems something very wrong has happened to Bluetooth on my laptop in upgrading to Monterey. And BTW the Debug mode you suggested doesn't work in Monterey, only in Big Sur. Apparently you have to go into Terminal in Monterey, which I tried, but the phrase I pasted in from the article I was reading didn't work.

Any more ideas?

 

[clivechafer]

Update: I restarted my laptop and the two devices reappeared. I can now once again listen to my music through the Denon receiver, but only at maximum volume on both devices.
Second update: I touched the volume down button on the laptop keyboard (top row, 3 from the right)... and the volume went up, dramatically. It is now playing closer to its volume before all this started. No idea what worked. I dragged the PLIST to the trash again and restarted my laptop, so maybe that worked this time, although I hadn't twice before. Anyway, I'm going to see what happens over the next 24 hours. Thanks for your help.

 

[newbutter]

Hmmm. Since resetting the Bluetooth module didn't work, and the volume issue seems random, I wonder if this could be related to a software bug in Monterey itself.

In the meantime, you might also try creating a new user account on your Mac and checking if the Bluetooth issues persist there. If they don't, it might suggest a user-specific issue rather than a system-wide one.

 

[clivechafer]

Thanks, newbutter. I agree, it definitely sounds like a bug. Pity Apple decided to remove debug mode from Bluetooth. Seems pretty clear there's still a need for it. If it recurs I'll try adding a new user, but for now it seems to have stabilised. Thanks for the suggestions.