Several weeks ago maybe in an early 15.4 Beta suddenly Universal Control appeared in the Menu Bar Display Settings.
I never really heard of it or used it before. Somehow the settings were already activated. A few months before I saw the mouse courser on my iPad and wondered what that is, but forgot about it because I almost never use iPads.
It worked for a few weeks and was perfect for using a Mac mini with one Display and iMac next to each other. Then I removed a Thunderbolt 4 Dock from my iMac, moved everything on my desk a bit and it was suddenly gone. Of course the first thing I did was putting everything to the same place as before. The mini is even under the iMac display now. But nothing helped.
I tried everything to activate it again, even logged out of iCloud on both Macs. The display from the other Mac is still visible in System Settings of boths and when I click on one of them I only have those options:
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But I want those:
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Also this is running on both Macs:
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Handoff is turned on for both, both have Wifi an BT enabled and are on the same network, incoming connections are allowed for Universal Control in the Firewall, it worked with VPN on before, but I of course tried turning that and Adguard too off.
The Macs are M3 and M4 Pro, so also no big age difference. I tried if it might work with my M2 Pro MacBookPro on one of both Macs but that also did not work. For the iPad only display sharing no mouse courser anymore.
Every solution I found was just an instruction how to activate it. Or parts of it.
Since it stopped working, suddenly apps that are in use on one Mac like Mail or Notes appear in the Dock as last icon on the right side. Those Continuity/Handoff options had not been there before when Universal Control worked.
I almost never used Bluetooth before and switched to Ethernet from WiFi last year, so BT was turned off on my other Macs since and iPhones since years most of the time before and WiFi later on the Macs.
Sometimes when I needed Universal Clipboard for pasting something to an iPhone I turned it on for a while. But otherwise all this is new to me. I knew about most Continuity features, but I never really used them.
Universal Control was an exception I never heard of it until I found it in System Settings. I didn't even know how it is called. Sidecar for iPads was the last I heard of.
Before that I used only one M2 Pro MacBook Pro for a year and before that I had for many years only Macs with nothing newer than High Sierra installed. So I maybe missed it's introduction.
It just was there suddenly in February this year and gone a few weeks later in March without changing anything special in macOS or doing an update to a new beta.
Both Macs have a Thunderbolt Bridge and the Ethernet connections to the Router too and I wonder why I can't use this for such features.
Is it maybe possible to use those sharing options instead? I can only copy files over in Finder but not just drag them with the mouse on the other screen.
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