primary mouse button changing every time i start the computer.

Hello, thank you for reaching out to Microsoft Q&A.

To determine whether the issue is with the mouse itself, try using a different mouse and check if it behaves correctly every time you start the computer. If the other mouse works as expected, the original mouse is likely the cause where it needs to be

However, if you experience the same behavior with a new mouse, or if you don’t have another mouse to test with, we can try updating or reinstalling the Bluetooth drivers to see if that resolves the issue.

To Update Drivers:

• Go to Device Manager.
• Expand the arrow next to Bluetooth.
• Right-click your generic Bluetooth driver (Intel (R) Bluetooth or Realtek), select Update driver, click Search automatically for available drivers, and click Update.

If Windows cannot find any updated drivers, check whether you can roll back the drivers.

To Uninstall Drivers:

• Remove your Mouse from the Bluetooth paired lists.
• Then go to Device Manager and expand the Bluetooth section.
• Right-click your generic Bluetooth driver, such as Realtek (R) or Intel Bluetooth driver, select Uninstall device > Select 'Attempt to remove the driver software for this device' check box, and click Uninstall.
• Once uninstalled, restart your computer and pair your Bluetooth Mouse and change the Primary Mouse buttons.

Restart your computer and see if it is working.

Windows stores the primary mouse button setting in the current user profile. If it keeps reverting on every restart, focus on setting it through Windows Settings and checking for profile or device issues.

1. Set the primary mouse button again in Settings
   1. Select Start > Settings > Bluetooth & devices > Mouse.
   2. In Primary mouse button, select Left (for left‑handed use).
   3. Close Settings and sign out, then sign back in and verify it is retained.
2. Check for conflicting mouse or accessibility settings
   1. Open Settings > Accessibility > Mouse.
   2. Make sure Mouse keys or other interaction options are not forcing alternate behavior.
   3. Go back to Settings > Bluetooth & devices > Mouse and confirm the primary button is still set correctly.
3. Verify mouse‑specific software If the mouse has vendor software (for example, from the manufacturer) it may override Windows settings at startup. Open that software and look for handedness/primary button options and set them to match Windows, or disable any profile that changes button mapping.
4. Test with another mouse or user account
   1. Connect a different mouse and set the primary button again in Bluetooth & devices > Mouse.
   2. If the setting persists with another mouse, the original device or its software is likely forcing the change.
   3. Create a new local user account and log in; set the primary mouse button there. If it persists in the new account, the issue is profile‑specific in the original account.

If none of the above resolves it and the setting continues to reset only on this build, capture the behavior (steps to reproduce, build number, and whether it happens on a new account) and report it via the Feedback Hub so it can be investigated as a potential regression in that Windows 11 build.

References:

• Change mouse settings
• Make your mouse, keyboard, and other input devices easier to use