the wheel does not scroll, jumps, or scrolls differently than expected
Scroll failures can involve the wheel encoder, browser/app behavior, horizontal-vs-vertical mode, or connection instability.
Do not jump to the most invasive fix
Do not assume cursor movement proves the wheel is healthy; mouse movement and wheel events are separate inputs.
Retest the same condition
A useful retest shows consistent wheel events in the intended direction without unexplained reversals or jumps.
Rule out the simple causes
- 1
Run DeviceOK Scroll Wheel Test and watch whether wheel events arrive consistently.
- 2
Check the operating-system mouse wheel settings and scrolling direction.
- 3
Clean around the wheel according to the mouse maker's guidance and compare another app.
Work through the problem in order
- 1
If DeviceOK receives clean wheel events but one app behaves incorrectly, focus on that app/browser behavior.
- 2
If events are intermittent across apps, compare another USB port/receiver/Bluetooth connection and another computer if practical.
- 3
Use the manufacturer's support path before replacing a high-value mouse.
Consistent wheel events make a completely dead scroll encoder less likely and point toward app/settings behavior.
Missing or erratic events in DeviceOK and another app make the mouse connection or wheel mechanism more plausible.