Signs of an unwanted double click
A mouse that double clicks on its own usually gives itself away in everyday use. You might notice:
- Folders or files opening when you only meant to select them.
- A single click in a text box selecting a whole word.
- Dragged items dropping halfway, or a drag that never starts.
- In games, two actions from one press.
The usual cause is a worn switch under the left button. As the contacts age, one press can register as two presses only a few milliseconds apart.
How the 80 ms check works
On this page the double click check is highlighted at the top of the tool. Click inside the box with single, unhurried clicks. Every time you press the left button, the tool measures the gap since the previous left press.
If two left clicks arrive less than 80 ms apart, the tool adds one to the suspect count and writes a highlighted warning to the log with the exact gap. A person very rarely clicks that fast on purpose, so a gap that short most likely means one press was counted twice. The panel also shows the shortest gap so far and how many real double clicks your system recognized.
Keep clicking for a while. A worn switch can fail on some presses and not others, so a short test can miss it.
What you can do about it
Start by ruling out settings. Check whether your mouse software or operating system has any button set to send a double click, and look at the double click options in your mouse settings. Then try the mouse on another surface and, for a wired mouse, plug it into another USB port. For a wireless mouse, reconnect it. Test again after each change.
If suspects keep appearing with slow single clicks on every port and surface, the switch itself is probably worn, and no setting will fix that. Check whether your mouse is still under warranty before you replace it.
Fast clicking and this check
Butterfly clicking can create very short gaps on purpose, so click slowly here and any short gap clearly comes from the mouse. Fast techniques also add wear to mouse switches, so check now and then if you use them.
To measure clicking speed instead of faults, use the CPS test. For the other buttons and the wheel, see the mouse test.