High Performance Screen Sharing not working? Here’s what finally fixed it for me.
Connected to my Mac mini over USB4 and selected High Performance with one virtual display. Still painfully laggy, and Dynamic Resolution was grayed out.
Turns out, switching to View → Adaptive Quality in the active session made Dynamic Resolution available and everything felt way smoother. Still worked after reconnecting, too. This was in the session’s View menu—not the default quality setting in Settings.
Apple, please look into this. Users shouldn’t have to stumble onto a random menu toggle to get the mode they already selected to actually work.
macOS 26.5.1 @AppleSupport