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The scroll wheel seems to malfunction. As I scroll eg down the page will move down, suddenly move up.

It also looks as if it does not scoll a consistent distance. Sometimes one line, sometimes more.

The same problem crops up in Corel Draw when the mouse is used to zoom in and out. It will erratically zoom in and out even the wheel is moved in one direction only.

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marked as duplicate by karel, BlueBerry - Vignesh4303, JakeGould, Scott, Twisty Sep 9 '15 at 21:26

This question was marked as an exact duplicate of an existing question.

This could be many, many things. Starting with a malfunctioning mouse, a wireless mouse with little battery left, malfunctioning software, ... please check those simple reasons, and give full details if the problem persists. – vonbrand Apr 11 '13 at 10:02

Assuming that is the only issue, you probably have dust or hair in the mechanism. Try to blow it away.

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