Multicam weirdness

Multicam is just not working at all for me. I’ve been editing multicam clips in Resolve this way for more than a year, so I don’t understand what is happening.

This is Resolve 9.1.3 running on a M4 Pro MacBook Pro, OS 15.2. It is happening the same way on a M1 Mini (OS 15.2) running Resolve 9.1.2. This is a Cloud project, with all the mostly 4K media on a local SSD.

After selecting all the clips in the media pool and creating a new multicam clip from selected clips, I mouse over the multicam clip and the three camera views pop up as normal in the Source monitor. But when I right click on the multicam clip and say open in timeline, and change the Source monitor view to Multicam, the Source monitor goes blank. Just black nothing.

I am attaching two screenshots, one of what the interface looks like when I mouse over (but don’t yet open) the multicam clip, which looks normal, and one of what happens when I tell Resolve to open the MC clip in the timeline. [EDIT: Apparently saved the wrong screenshot for the open-in-timeline view. The lefthand source viewer should be just blank. Argh.]

This project would normally take me a day, and of course is due tomorrow, and I have spent all day trying to figure out what to do. I have restarted Resolve. I have restarted the computer. I plugged the media drive into the M1 Mini and opened the same project there. All the same result: The grid of camera views doesn’t appear in the Source monitor. Nothing appears in the Source monitor.

I’m going to start over and create a new project and see what happens, but I wanted to see if anyone here had any thoughts.

Also: The first time I created a multicam clip and opened it in the timeline, the MC interface actually appeared in the Source monitor as normal. But I had forgotten to check the Detect Clips From the Same Camera box, so a bunch of clips were missing. I tried adding them manually to the multicam clip that was open in the timeline — which I have done before, many times — but after doing that, the Source monitor MC grid would not appear. So I deleted the MC clip, reselected all the same clips in the media pool and created a new multicam clip. But the Source monitor appears to be permanently black in multicam mode. No cameras grid, no cursor changing to a razor when it’s over the Source monitor, no pressing 1, 2 or 3, etc.

Any ideas would be much appreciated.

when I right click on the multicam clip and say open in timeline, and change the Source monitor view to Multicam

That's not the correct process.

Add the Multicam to a timeline, then change the Source Viewer to Multicam mode.

The Open in Timeline command is only if you need to change something in the Multicam. It's not for cutting.

As Jim said. Also you can check Sync Bin for multicam editing on the cut page. Might offer more flexibility.


QUICK TIP: SYNC BIN in DaVinci Resolve

I know I'm just being a blockhead here, but I think I'm missing a step in the setup process for Multicam, but can't figure out where I'm going wrong. (please be gentle... I know this is a really stupid problem with an obvious fix, but I've been working it for three days and just can't get it.). This was the thread that seemed to most closely match the issue I am having... I apologize if it's in the wrong place, but I don't have a lot a experience working in forums.
I typically have an edited BM ATEM project file to work with here, but during the shoot we briefly lost our online feed and our connection to our local hard drive storage device, forcing me into "recovery mode." Both cameras were recording to SD cards, so that was my "Alamo." I have transcoded the SD files and imported them into my DRv19.1.3 Build 7 project.
I am editing a simple 2-camera (with jam-synched timecode as well as audio recorded on both) dance recital shoot, with a title image at the beginning of each routine. I need to cut the project into individual routines, that I can upload to an online "gallery," for access by the dancers' families.
I located the point where our project got interrupted, and the point where we got back online after a restart. Turns out that I need to salvage, I think, seven routines this way. So I loaded both of the transcoded files from the SD cards onto a timeline, and roughly cut away the material from before and after the equipment failure, leaving me with the two angles of continuous recording, covering the seven routines I need.
I did a "rough synch" with these two files stacked on the timeline, and cut them into the seven individual routines. (Here is where it appears I deviate from "common practice," but it seems like it "should work" to me...). I select the two segments of the timeline (Cam1 and Cam2) and Control Click to copy them. Then I created a new timeline from the "file" dropdown, and pasted the two clips into the new timeline. (If I was supposed to make new individual clips out of these and put them into a new media bin somehow, I wasn't able to figure out how to get them there.)
I was eventually able to convert this timeline into a Multicam timeline, but never could get the source viewer to work properly. At the moment, I don't even remember how I got the timeline converted to a Multicam! (My brain is basically tapioca, from trying to fix this issue!). At one point, I got as far as being able to play both angles in the viewer, but the playhead wasn't moving on the timeline... so I'm not really sure what I was even looking at in the viewer... and trying to insert razor cuts appeared to have no effect on the project.
I'm sure something about the way I've handled this footage is causing this problem, and at this point, I'm willing to go all the way back to importing the recovered footage from the SD cards if necessary. Of course, if there's a way to use the segments I already cut up on the timeline, that would save me a bit of time... but since I'm sure the problem here is my workflow, I'm willing to learn to do this the "right way."
Of course, I'm against a bit of a deadline here, so I'd appreciate whatever compassionate help you might be able to offer. I've watched about 8 different Youtube videos dealing with Multicam editing, but they all have either skipped over the part I messed up on, or if it was there, I missed it in every video. I tend to be a rather visual, bullet-point learner, so a simple list of "production flow steps" would probably be most helpful.
Thank you all in advance for your patience, and your assistance.