47

On my Windows 7 system, and in all programs, when I scroll down with my mouse, it will scroll partway down then then scroll partway up. It is totally erratic and is driving me crazy.

I do have a wireless keyboard/mouse, but I do not use the mouse, as it does not work: I have replaced it with a "wired" mouse.

I have tried adjusting the mouse settings (number of lines to scroll, and turned off "acceleration, as I think it was called).

Does anyone know how to fix this?

jvriesem
  • 115
  • 10
bnieland
  • 629
  • 1
  • 6
  • 9
  • Are you scrolling with a scroll wheel, or by grabbing and dragging the scroll bars? – Ƭᴇcʜιᴇ007 Jun 17 '11 at 00:19
  • With mouse wheel. Tried different mouse, and no problems. – bnieland Jun 23 '11 at 15:15
  • 1
    I hate to throw a "me too" onto this, but here it is. I have scoured the farthest reaches of the internet and have not found anyone with this exact problem until now. I'll try to come back and post an answer if I ever hear of one. – Jesse Slicer Mar 20 '12 at 18:32
  • When you say that it scrolls back “someway” in the opposite direction, exactly how much do you mean, one click of the wheel or a lot? – Synetech Aug 29 '12 at 04:38
  • 1
    It's a "two steps forward, one step back" kind of thing. – Umopepisdn Nov 27 '15 at 19:47
  • I've blown it with a special compressed air spray. It still behaves the same :( – SuperJMN May 12 '18 at 17:01
  • I'm experiencing this with Logitech G403. Blowing with a compressed air spray didn't work. – SuperJMN May 12 '18 at 17:02
  • This problem is not *always* dust and not just typical of scroll wheel mice... there's at least one instance where the issue was actually a firmware problem. This improved the behavior of my Logitech G403 although I don't think it fixed it entirely (hard to tell as I've been troubleshooting this so long) https://community.logitech.com/s/question/0D55A00006zB4MbSAK/g403-scroll-wheel-goes-opposite-directions-randomly-fix – okonomichiyaki Oct 07 '18 at 15:25

4 Answers4

42

It's dust.

No, really: it happened to me many, many times, and the cause so far has always been dust inside the mouse. It gets trapped in the scroll wheel and interferes with the sensors.

In order to solve it, open it and clean the wheel — or, if it's a cheap model, I recommend buying a new one.

That Brazilian Guy
  • 6,834
  • 10
  • 64
  • 102
  • 1
    Not if you're using an ergonomic mouse – autonomatt Jan 07 '15 at 16:35
  • 3
    I have had this happen a couple times - dust or crumbs is usually the problem (though it has been a failing component as other answers suggest). Try blowing into the wheel while rolling it (or better used use compressed air), this generally clears the dust without having to dismantle everything. – brichins Nov 18 '16 at 17:13
  • 12
    Wow i blew on it for 2 seconds and problem solved. – Ben Dec 24 '16 at 02:40
  • 2
    I must confirm that blowing on it a few times made it better, but didn't completely fix it. Compressed air is probably the best option. I doubt it will fix it for good, but it will make it better. For a permanent fix, maybe Synetech's answer would be better. – Ismael Miguel Oct 05 '17 at 10:19
  • 3
    Blowing on it 2-3 times completely fixed it for me. – QuantumBlack Dec 13 '17 at 22:19
  • "the cause is _always dust_" is quite overconfident a statement, and it's definitely wrong in case of older mice with worn-out wheel bumps and perfectly clean sensors and wheel housing. In that case, the correct answer is **Synetech's** – sunny moon Mar 07 '20 at 09:01
  • This also worked for me. At first, I just tried to get rid of the dust by blowing air in the wheel and cleaning it with wet paper. This worked for several minutes and then stopped. Then I dissambled the mouse and cleaned the laser lense. It works since a day without issues. – MJQZ1347 Aug 30 '20 at 10:57
  • @sunnymoon I meant the case is always dust **when it happens to me** (still true six years later). Of course, there are many other possible causes. I'll edit out the ambiguity of the statement. – That Brazilian Guy Sep 01 '20 at 16:14
  • Had the same problem. I opened the mouse, removed the wheel, blew 3-4 items on the unit holding the wheel and then fit the wheel back properly into the groove. That solved the problem. – rks Apr 08 '21 at 06:21
  • @autonomatt, I didn't think that it was the cause of the problem of my ergonomic mouse as it was brand new, but it worked. I blew on it (with my mouth) several times while turning a bit the wheel as the same time (I also had to repeat this a couple of time like 3-4 times in an hour). – MagTun Aug 09 '21 at 15:45
25

Assuming that the amount of back-scroll is only a single click of the scroll-wheel and not half-way up or down the page, then what you describe is typical of wheel-mice, especially older ones.

If you open a wheel-mouse and look at how the scroll-wheel mechanism works, you’ll see that it has a series of bumps inside the wheel and a spring that presses against the bumps to cause the click-y feeling. Moreover, you’ll notice a series of thin slits on the face of the wheel through which a small beam of infrared light passes, and the mouse detects the interruptions as the wheel rotating.

The problem is that the bumps inside the wheel (“resting positions”) are not always perfectly aligned with the slits. This can be exacerbated with age due to wear. As such, when the wheel is rotated, the mouse things it has stopped scrolling, but when you release the wheel, it settles in the bump, causing a slight rotation forward or backward.

There’s not a whole lot that can be done about it, but one option is to open the mouse and remove the spring altogether (the one with an end inside the wheel, not the one holding the wheel up). Personally, I find it better because then the mouse has no clicking at all and feels smoother. In fact, it is quite desirable because excessive clicking with some mice can create a big headache due to all the vibrations. The problem of course is that if the wheel is too loose, then it may spin too freely and cause its own erratic scrolling issue.

Synetech
  • 68,243
  • 36
  • 223
  • 356
  • 2
    @bnieland: this should probably be the accepted answer. The currently accepted answer does seem to help, but this is a better answer. – jvriesem Sep 04 '15 at 05:09
  • 2
    When I disseambled my mouse I figured out the problem. Plastics sticking out of the top of my mouse which were supposed to be holding wheel ends, were actually displaced, and so my wheel was dancing between the clicking plastic mechanism. I just had to put it in the right place and problem was gone. My scroll is no longer jumping inside back and forth. Both ends are placed in those plastic holdings, so everything works fine. – Kamil Gosciminski Sep 20 '15 at 21:38
  • Worked like a charm! Thanks alot. – Denn May 24 '21 at 10:59
6

I just switched the number of scroll lines from the default (3) to 5 lines and this seems to have stabilized the erratic behavior.

Cee
  • 92
  • 1
  • 2
0

If it has a mechanical wheel encoder, swap the encoder with a new one, it'll need some soldering and an identical sized mechanical encoder.

Recently I disassembled a mechanical encoder, by the looks of it there is no way to service it. The three legged spinning prone is too thin and fragile, no way to delicately scratch off some potentially presented oxidation/dirtiness on any of the contact surfaces, I got no tweezers and other more sophisticated tools so I just roughly scratched the opposite contact stripes and bended the prongs towards the stripes further, only to find out the scrolling reaction has gotten worse after assembled the whole mouse back together.

Sij
  • 17
  • 3