For the last couple weeks, I've been (finally) working on some Moom videos. And while I personally don't use Stage Manager, it was ideal for the first video, as I needed to keep switching into and out of Moom's settings, and didn't want to leave app windows cluttering the screen.
But I ran into a problem…I generally record with ScreenFlow, and when I tried to do something in System Settings, I would run into a massive delay—30 or so seconds before my clicks would take. And when I tried to record an onscreen pop-up menu that users can resize, it only showed up in about one of 20 frames.
After a lot of troubleshooting, I found the cause of the problem: Stage Manager itself. And while the first glitch only affected ScreenFlow, the second occurred in both ScreenFlow and Apple's built-in recording tool.
Here's how both look in action:
As soon as I disabled Stage Manager, both issues went away. I have reported this bug to Apple (#FB22517070), but I don't know that they'll do anything about it. I hope they will, as it's incredibly disruptive and prevents using Stage Manager when making videos, which seems like a prime use.
I also reported the issue to Telestream (ScreenFlow's company), and they did some more technical troubleshooting; here's what they told me; I included this in my bug report:
I’ve been looking into that System Settings hang on macOS Tahoe 26.4.1 and was able to replicate it consistently here on 26.3.1.
During the freeze (which lasted right around 30 seconds), I ran a process sample on System Settings and saw the main thread sitting in mach_msg2_trap through NSRemoteView. It looks like System Settings is getting stuck waiting on XPC communication with its out-of-process UI components while WindowServer is handling both the ScreenCaptureKit stream and the Stage Manager transition.
The timing of the delay is very consistent at around 30 seconds, which lines up with the kind of timeout behavior you typically see when something in that path stalls and eventually recovers (possibly a watchdog). I also tested a few single-process apps like Notes and TextEdit under the same conditions and they resumed instantly, which makes this look specific to the ViewBridge/remote UI side of things.
At this point it looks like a macOS-level issue that’s being exposed by the recording stream rather than something happening inside ScreenFlow itself.
Thanks for documenting this so thoroughly this is exactly the kind of bug report that actually helps people. I had written off some weird recording delays as my machine being slow, but after reading this I'm wondering if Stage Manager was the culprit all along.
The technical breakdown from Telestream is really fascinating. The fact that it consistently hits that 30-second mark and only affects apps using ViewBridge/remote UI components points pretty clearly to a macOS-level issue rather than anything ScreenFlow is doing wrong. It's good that Telestream dug that deep instead of just saying "not our problem."
Hopefully Apple acts on this Stage Manager and screen recording feel like a pretty natural combination, especially for anyone making tutorial or walkthrough videos. Fingers crossed the bug report gets some traction. Will definitely be keeping Stage Manager off during recordings until this is resolved.