Issues after Update Mac OS 26.3.1

I am having the exact same problem, and it sounds like you and I are on the same type of devices/software with the same presentation setup. I’m hoping this becomes a hotfix from Apple/Keynote soon. In the meantime, the only workaround I’ve been able to find is 

In Keynote:

1. Use Play → Play Slideshow in Window
2. Drag that window to your external monitor
3. Manually resize it to full screen

Then in Zoom:

1. Share that window (not the entire screen)

You still get presenter view on laptop, slides on external display and full access to chat, participants, polls. But I haven’t found a way to customize the presenter display in this mode, which makes using notes, watching the clock or previewing slides less than ideal.

Good luck, and PLEASE do reply if you find another fix to this.

Hi,

I’m experiencing the same issue after updating to Mac OS 26.3.1. Before the update, chat, video, and participant windows would stay in the foreground during Keynote presentations, even in full-screen mode with two monitors. Now they get hidden behind Keynote.

It seems related to how macOS handles window focus with full-screen apps on M1 and M4 Macs. A few things that might help:

• Try using “Windowed Full Screen” mode in Keynote instead of true full screen.
• Check Mission Control / Display settings to ensure “Displays have separate Spaces” is enabled.
• Some users report that restarting Zoom after a macOS update helps temporarily.

Would love to hear if anyone has found a permanent fix.