Screen Sharing High Performance option suddenly broken

PPIAVP wrote:

I have a MacBook Air (M4, 2025, Sequoia 15.5) that I use to connect to a headless Mac Mini (M4 Pro, 2024, Sequoia 15.5) via the Screen Sharing app. It connects in Standard mode flawlessly.

Up until about a week ago, it connected in High Performance mode flawlessly as well. I can't think of anything that may have changed. Now it hangs on a grey screen when trying to connect and gives the error message:

This Mac was unable to start a High Performance connection to "David's Mac mini". Change the screen sharing type to standard and try again.

The Mac Mini is plugged in to Ethernet I've tried the MacBook Air on both Wi-Fi and Ethernet with the same results. I imagine it can't be a connection issue, as I can still connect in Standard mode.

Any advice on how to troubleshoot or at least access why the High Performance mode is suddenly failing?

see if there is anything here—

Use High Performance screen sharing - Apple Support

SafeBoot Start up your Mac in safe mode - Apple Support will sort many anomalies

Login and test. Reboot as normal and test. Caches get rebuilt automatically.