Adjust mouse scrolling direction with Mos

Before you start

• Use an external mouse with a scroll wheel. Mos is a third-party app, not a built-in macOS setting.

• Mos needs system permission to process mouse input. In the current English macOS 27 interface, the entry is Device Control and Data Access; earlier versions use Accessibility. Read the access scope shown by macOS before granting permission.

• The macOS 27 permission label was verified in English; localized labels may differ. The Mos controls were checked in version 4.2.1 and may vary in other versions.

Settings path

Mos website or GitHub Releases › Download Mos › Move it to Applications

System Settings › Privacy & Security › Device Control and Data Access (macOS 27) › Allow Mos

System Settings › Privacy & Security › Accessibility (earlier macOS) › Allow Mos

Mos › Preferences › Scrolling › Invert wheel direction

Steps

1. Keep Natural Scrolling turned on in System Settings > Trackpad > Scroll & Zoom.
2. Download Mos from its official website or GitHub Releases, then move Mos.app to the Applications folder.
3. On first launch, read the system permission request. If you accept the access scope, allow Mos in System Settings > Privacy & Security > Device Control and Data Access. On earlier macOS versions, use Accessibility.
4. In Mos itself, open Preferences > Scrolling and enable Invert wheel direction. Enable smooth scrolling only if it improves the feel of your mouse.
5. Scroll the same webpage with the trackpad and the mouse. Confirm that the trackpad keeps Natural Scrolling while the wheel uses your preferred direction.

Before

When you rely only on the macOS scroll-direction setting, the mouse and trackpad use the same direction. Natural Scrolling may feel right on a trackpad but unfamiliar on a mouse wheel.

After

Mos processes the mouse wheel separately: the trackpad can keep Natural Scrolling while the wheel uses the direction you prefer, with optional smooth scrolling.

Things to check

• Running another mouse-management utility at the same time can apply scroll direction or smoothing twice. If scrolling behaves unexpectedly, test with only one utility enabled.

Undo the change

• Turn off reverse scrolling and other scroll processing in Mos, or quit Mos.

• If you no longer use Mos, turn off its permission in Privacy & Security > Device Control and Data Access (Accessibility on earlier macOS versions).

Sources and version notes

• Mos — Separate mouse and trackpad scrolling behavior
• Mos on GitHub — Features, installation, and Accessibility permission

This guide records a path review for macOS 27.0.1 on 2026-10-14; labels may differ on other versions.

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