I have posted for months in the feature / bug request form, but I have never seen a respone or an attempt at fixing this bug as they have released a non-beta that suffers from this problem as well as the current beta:
I am using an M1 Mac mini and it took me a while to identify the root cause of this bug, but now I have narrowed it down and it happens every single time. If a second monitor is attached and you try and open a previous project you will see the timeline load and then the beach ball will stay spinning no matter how long you wait. It does not matter if the project was setup to output on the second monitor or not. It will just freeze like this. The only work around is to force close premiere and physically disconnect the second monitor. Even turning the monitor off will not fix this issue since the Mac still knows something is connected to that port. I have been hoping to see this fix for months now, but even the latest version still suffers from this bug.
Thank you for your help!
Here is my info:
Model Name: Mac mini
Model Identifier: Macmini9,1
Chip: Apple M1
Total Number of Cores: 8 (4 performance and 4 efficiency)
Memory: 16 GB
macOS Big Sur 11.4 & 11.5
Premiere Pro 15.4.0 BETA (Build 40) - 22.0.0 Beta (Build 39)
I've not seen any other Mac user post this, but I could easily have missed it.
What troubleshooting steps have you done? Like trashing prefs, dumping cache files, try new project files, what?
My suspect is that not many people are running the M1 Mini with dual monitors.
I have tried several versions of Big Sur as well as at least a dozen versions of Premiere Pro. Including wiping the Mac Mini and starting from scratch (fresh install of Big Sur), so that should take care of the preferences and casche files.
I have started new projects, tried old projects, but it all comes back to having to phiscially dissconnect the second monitor before Premiere will load a previously saved project that was saved with 2 monitors plugged in. I can make it happen 100 percent of the time, i.e. I have never had it work, not even once with dual monitors connected when trying to load a saved project.
Hoping we get some other M1 Mac people on here. I do know from comments engineers have run multiple monitors on M1s ... they do that on any OS/form they build for. But naturally the number of computers they can run in-house is rather small compared to "out in the wild".
I haven't seen much in the way of comments about this from M1 users, but it would be good to get some other responses ... how many have the same problems you do?
And of course, @Kevin-Monahan is a total Mac dude ... would love to get his participation here.
Hello Makers Acres:
Sorry to hear you're running into a dual display issue on your M1 Mac mini. I'm not seeing an issue with having two displays connected with mine. That is, Premiere Pro works as expected with my usual dual display setup with with the undocked Project tab on the left monitor and everything else on the right monitor. It also works as expected when I choose one of the displays for playback via Preferences > Playback > Enable Mercury Transmit.
The left monitor is patched via HDMI out of the M1 Mac mini to the HDMI in of a 29.5-inch Dell UP3017 running at 2560-by-1600 and the right monitor is patched via Thunderbolt out using an Apple Thunderbolt 3 to Thunderbolt 2 adapter to the Thunderbolt 2 in of a 34.5-inch LG Ultrawide (I forget the model number, but it's the 1st generation LG Ultrawide to include Thunderbolt from sometime around 2014/2015) running at 3440-by-1440.
I'm currently running macOS Big Sur 11.5.1, but the dual monitors setup worked fine back under 11.4 as well.
Something that might be worth mentioning is that I'd initially tried to patch the LG Ultrawide via Apple's USB-C Digital AV Multiport Adapter that converts UCB-C to HDMI and the display remained black and the M1 Mac mini did not show it in the Display System Preferences. I have not tried testing the adapter with another Mac to see if it might be a bad adapter or not.
I've included some screenshots below for reference below.
Have you had a chance to call AppleCare about the issue? Maybe even bring the M1 into an Apple store for testing?
Have you tried different cables/adapters?
Have you tried a clean install of macOS and Premiere Pro, testing Premiere Pro prior to installing any other software?
Also, just to clarify, you're having this issue with both the current release of Premiere Pro 15.4.0 (Build 47) and the Beta?
Thank you for the info. This only appears to happen with Premiere Pro, but the Beta and the Current stable release. I have tried a full blown clean install of both the OS and Premiere with no difference. This is fixed by unplugging my second monitor (the one slected for playback), then restarting premiere pro, then plugging the monitor back in after the project is open and my second montor works fine as the playback monitor. I have a similar setup to you, and I do have a powered HDMI to DVI convertor so I can have my second screen. If it is the convertor causing the problem, I would think this bug would still be related to Adobe hanging on something. I am also running this through a KVM, but once again, I think Adobe should be able to handle this.
As far as your adapter, my understanding is that the Mac M1 Mini only supports HDMI and one USB-C monitor. You can't connect two monitors to USB-C ports with or without adapters period.
Here is a video of the failure in action:
See attached screen shots...