Why does editing one monitor’s system configuration change another monitor too?

System-configuration overrides apply to every display with the same vendor and model identifiers. Two monitors can have separate BetterDisplay entries while still sharing the same model-level override.

This affects edits under System Configuration and Flexible Scaling, including native dimensions, generated scaling choices and the edited system display name. Changing BetterDisplay’s identification method to System UUID match, forgetting a saved display or resetting its app settings does not make this model-level configuration specific to one physical unit.

For the underlying rendering method, see what flexible scaling and custom resolutions change.

Before applying an edit, read the editor’s scope notice and consider every matching monitor, including one you may connect later. If you only want an app-level preference or label for an individual display, use the corresponding per-display setting rather than changing the model’s system configuration.

To label identical monitors Left and Right inside BetterDisplay, open Settings > Displays > [display] > Additional Settings… for each display and set Custom displayed name. This changes the app’s label, not the model-level system name. Stable per-display naming still depends on macOS and BetterDisplay being able to distinguish the physical displays. Identical identification data can cause saved identities to be mixed up.

See System Configuration for shared overrides and display identification for how BetterDisplay matches individual displays to saved preferences.