Universal Control frequently disconnects between M2 Mac Mini and M1 MacBook Pro

The whole thing really seems to be exclusively a Bluetooth problem. I have now found a workaround that has been working for days without any disconnects between my MacMini M1 and MacBookPro M1 Pro under Sonoma 14.5.

If you want to reproduce it (do it for both Macs):

• Reset Bluetooth controller with Terminal command:

sudo pkill bluetoothd;sudo shutdown -r now

Attention: Mac restarts immediately!

• Activate Bluetooth sharing and pair both Macs once in the Bluetooth settings.

Fixed (for me)! Universal control should then work without any problems.

If so, Bluetooth sharing can probably be deactivated again (try it out!).

I hope this works for you too. I am grateful for any feedback!

Regards

Tom

Hi @i.am.joel

In my case no problems/disconnects since weeks!

I've tried lots and lots of advice and solutions myself before, all of them - on their own - without any (lasting) effect.

My solution then was (exactly in the order described!):

Before I switched on Bluetooth sharing, I also switched off Handoff and Universal Control on both Macs, reset the Bluetooth controller and then restarted both macs.

(on Sonoma use `sudo pkill bluetoothd;sudo shutdown -r now` in terminal to reset and restart the controller)

Then I turned on Bluetooth sharing, paired the two Macs with each other, then Universal Control on and Handoff back on.

Since then, Universal Control has been working without any problems, as Apple probably intended.

Good luck.

Tom

Try this hint first:

. disable Universal Control in Displays

. disable Handoff

. disable Bluetooth Sharing, if enabled

. restart your Macs

. delete Library/Preferences/com.apple.bluetooth.plist

. reset Bluetooth Controller (again) as mentioned in my first post -> restarts macs

. re-pair your disconnected Bluetooth devices (mouse, keyboard etc.), if necessary

. switch on Bluetooth Sharing and pair Mac1 with Mac2 and Mac2 with Mac1

. Switch on Universal Control and reactivate Handoff

Good luck.

Hm, good question Joel.

In my case, Universal Control worked without any problems for the first time after I switched on Bluetooth sharing and paired the two Macs with each other. After that, I deactivated the sharing at some point and it still works today.

It may have been due to this, but not necessarily.

If it still works for you permanently, leave the sharing switched off.

I have only seen in the preference file `com.apple.bluetooth.plist` that there is an entry called `PersistentPorts` after pairing on each Mac. This also seems to define a Bluetooth channel (RFCOMMChannel) on which the two Macs communicate when connected. This is set to 3 on both of mine.

Since I suspect that the whole problem is exclusively a Bluetooth problem anyway, it could have something to do with the one-time activation of Bluetooth sharing.

Hint:

If your Macs communicate with each other mainly via LAN on the network side, it also works perfectly if the WLAN on one (or both) Macs is not connected to an access point. It is sufficient to simply activate WLAN on the Mac.

Regards

Tom

Translated with DeepL.com (free version)

Update: I have two external monitors connected to the 17" MBP (via a Dell hub) to which my mouse/keyboard are paired. The thought hit me that maybe this is a conflict between Display settings/positioning when it comes to moving to/controlling the 15" MBP. So I turned off "Push through the edge of the display to connect..." under "Advanced" right after I posted that last comment and this is the longest I've gone in FOREVER without seeing a disconnect from the 15" MBP. I left all of the other options under advanced turned on.

I hope I didn't just jinx things, but something else to try.

Interestingly, the two MBP are not connecting to each other via Bluetooth share from either side. They try but never connect. I do see them listed in each other's device list at least.

mac_pip wrote:

Anyway, I don't see why WiFi/Bluetooth is required.

It's likely related to the need for Apple Wireless Direct Link and/or Low Latency WLAN. If you run:

ifconfig awdl0
ifconfig llw0

You will see these interfaces configured with IPv6 link-local addresses, and it's likely that awdl0 will show "status: active". AWDL is a peer-to-peer Wi-Fi interface used by Apple for low-latency, high-speed communication between devices, and is commonly used for features like AirPlay, Sidecar, etc. which require quick and reliable data transfer. My guess is that it's also used for Universal Control. (llw0 is another low-latency Wi-Fi interface, which operates with an access point and is designed to minimize latency by avoiding power-saving modes, but it shows "status: inactive" for me.)

My latest idea is to look for Wi-Fi events along with Universal Control "sync" events, like this:

command log stream --info --style compact --predicate 'eventMessage contains "IO80211Family" OR eventMessage contains "com.apple.p2p" OR (subsystem == "com.apple.universalcontrol" AND category == "SYNC")'

in an attempt to try and find some correlation. But so far, nothing.

(I do find it somewhat interesting that the lines with "AWDL-CCA" show it checking 2 different 5GHz Wi-Fi channels. Channel 149 appears to be some sort of "master" control channel that gets used along with the 5GHz channel of the Access Point I'm connected to.)

Anybody else been doing an spelunking with log stream looking for nearby events that could provide a clue?

ok, here is a `full reset` for all those for whom it does not work with my simple method (do it on both macs):

. disable Universal Control in Displays

. disable Handoff

. disable Bluetooth Sharing, if enabled

. restart your Macs

. delete Library/Preferences/com.apple.bluetooth.plist

. reset Bluetooth Controller (again) as mentioned in my first post -> restarts macs

. re-pair your disconnected Bluetooth devices (mouse, keyboard etc.), if necessary

. switch on Bluetooth Sharing and pair Mac1 with Mac2 and Mac2 with Mac1

. Switch on Universal Control and reactivate Handoff

Perhaps this will finally do the trick ... good luck!

Tom

I have the exact same problem with almost the exact same setup ( I don't have the studio display). I have an M2 Mini as the main with an M2 MacBook Pro 13 as the side, and the Mini is connected to an LG HDR 4K display, both running Sonoma 14.3.1.

Universal Control was disconnecting 20+ times a day until I changed my whole WiFI setup from a TP-Link AC1750 to a Decco XE75; now, it disconnects maybe twice a day. The Magic mouse disconnects once or twice every two days, and the Magic keyboard works fine.

It worked perfectly on Ventura...

FWIW, I've gone the entire day without issue after 1) pairing the two Macs via bluetooth sharing AND 2) turning off "Push through to connect" under the Displays > Advanced settings for the MBP 14" I want to control. This has NEVER worked this long for me, there's always been multiple disconnects over the course of a workday, it was only a question of how many.

As I mentioned before, just pairing them on bluetooth share wasn't enough alone, the keyboard/mouse disconnected shortly after that. But once I also turned off the "push through" setting, it's worked like a dream all day.

Note: the MBPs are NOT actually connected via Bluetooth Sharing, but I see the other in the list of available bluetooth devices on each MBP.

Also note, no restarts on either machine as yet (I'm afraid I'll wreck a good thing!)

If I have more issues I'll try the rest of Tom AdS's solution, but I'm crossing my fingers that this continues now. I'll report back if I do run into issues and have to try that.

The feature seems to require WiFi to be turned on and in use depite the fact that my primary network is 2.5GB wired ethernet.

I seem to be able to resolve the issue by turning Wifi off, then back on again. Then turning "Allow your pointer and keyboard..." off in Displays->Advanced (hit "done") then turning it back on again (hit "done").

I don't know why it drops. My WiFi is solid, it doesn't drop. Both macs are just a few feet from the wireless router.

Anyway, I don't see why WiFi/Bluetooth is required.

This is incredibly annoying and definitely the worst thing about upgrading from Ventura to Sonoma. (It worked perfectly fine under Sonoma!) I'm using it to share an Apple Magic Trackpad and Apple Magic Keyboard with Numeric Keypad between two MacBook Pros.

What more can be done to troubleshoot this problem?

I'm running this in a terminal window:

command log stream --info --style compact --predicate 'subsystem == "com.apple.universalcontrol" AND category == "SYNC"'

(log is a zsh built-in; command calls the actual log binary)

This doesn't help at all with preventing the problem, but it does illustrate how often it happens — in case anybody knows any Apple engineers, has an open Radar or Feedback (or whatever they're called these days) and is looking for "data".

This is the kind of stuff I see when it happens:

2024-05-13 14:02:49.301 Df UniversalControl[905:1edb] [com.apple.universalcontrol:SYNC] Update Source Device: [31712345: [31712345: 1]] -> nil
2024-05-13 14:02:49.302 Df UniversalControl[905:1edb] [com.apple.universalcontrol:SYNC] Increment Sync Clock: [31712345: 3672, 83D12345: 99, A1A12345: 4388] -> [31712345: 3673, 83D12345: 99, A1A12345: 4388]
2024-05-13 14:02:49.305 Df UniversalControl[905:1edb] [com.apple.universalcontrol:SYNC] Connections: [A1A12345 (disconnecting)] -> []

2024-05-13 14:03:16.473 Df UniversalControl[905:1edb] [com.apple.universalcontrol:SYNC] IDS A1A12345: Device Available
2024-05-13 14:03:16.473 Df UniversalControl[905:1edb] [com.apple.universalcontrol:SYNC] Synced Devices: <private>
2024-05-13 14:03:16.473 Df UniversalControl[905:1edb] [com.apple.universalcontrol:SYNC] IDS A1A12345: available=true, valid=false

When I get disconnected (which happens a lot), often times it eventually re-connects automatically. Other times I can just un-minimize System Preferences (left showing the Displays pane because I have to use it so often) and then minimize it again. Other times I have to click the "Advanced..." button and turn off and back on "Allow your pointer and keyboard to move between any nearby Mac or iPad".

I haven't been able to figure out what triggers the disconnect — I need to figure out more things to include in the --predicate option to try and find a correlation with other events. For example, I'm wondering if it could be related to IPv6, perhaps with router advertisements and/or network reconfiguration.

If anybody with connections at Apple sees this and wants to work on tracking this down, feel free to contact me.

I've been frustrated by this problem for ages – and have similarly got into the same 'fix' pattern as others mentioned of having Prefs > Displays open all the time and then as soon as the connection drops on my 'second machine' (a MacBook that shares the keyboard and mouse from an iMac) then I CMD + Tab to get to the Prefs app, watch whilst the displays from the second machine re-appear, and then continue. Though sometimes I have also witnessed the actual 'lockup' described by others where the keyboard and mouse are unusable for about 10 seconds.

However, it's early days but for the past hour I seem to have found a fix... I've turned off Wifi > Ask to join Hotspots on both machines and everything seems to be working much better. The reason I'm hopeful this is a longer-term fix is that 'pushing through the edge' from the MacBook display to the iMac display seems to have become instantaneous, whereas previously there was sometimes a delay or I had to momentarily touch the MacBook trackpad.

I'll report back on how this goes but previously I was experiencing this up to 20 times in a working day, so anything less than that will be an improvement on this very frustrating bug.

None of the fixes in this thread worked for me - M2 MacBook Pro and a Late 2015 27" iMac running Monterey 12.7.6. Universal Control will randomly connect and work for a few minutes and then drop again. The Bluetooth connection to pair them won't hold for more than about 15 seconds before disconnecting and disappearing off of the discoverable list.

Turned everything off and installed Barrier last night. Free and super-easy to set up. So far it's working flawlessly.

I encountered the same issue, and what finally solved it was pairing my keyboard and mouse exclusively with one of my two Macs, and 'forgetting' the devices on the other machine. While this solution seems straightforward, it was effective. I regularly switch between two Macs (work and personal) that share a monitor, and since implementing this change, I haven’t experienced any disconnects. I believe the problem was that each time I switched machines, the second Mac was attempting to connect via Bluetooth, which interfered with Universal Control.

@jmpage2:

If you don`t have the com.apple.bluetooth.plist in `Macintosh HD/Library/Preferences`, then you have a big problem with your system configuration! Ths file HAS to be here, if your bluetooth Controller is installed and activ!

Do you have any other third-party Bluetooth-Drivers running in background (e.g. from Logitech)?

By the way, there are -besides Synergy- a few other apps, you can try (open source and free of charge):

First ist `Teleport`. You can find it here:

https://github.com/johndbritton/teleport/releases

I used it by myself for a long time and its working well in Sonoma and beyond. Teleport uses Apples Bonjour (TCP/IP), not Bluetooth and has nearly the same features than Universal Control. But can`t connect to iOS-Devices. It only works between two ore more Macs.

Second ist `UniControlHub`. Seems to be very new, I don`t tried it. It`s here:

https://github.com/rohitsangwan01/uni_control_hub

Tom