No, a watch winder cannot overwind an automatic watch. Automatic watches have a mechanism called a "slipping mainspring" which prevents overwinding by releasing excess energy when fully wound. This mechanism ensures that the watch is not damaged by over-winding, even if left on a winder indefinitely. Here's why:

Slipping Mainspring:
Automatic watches have a mainspring that winds when the rotor moves with the wearer's wrist. When the mainspring is fully wound, it has a built-in clutch mechanism that allows it to slip, preventing further winding and potential damage.

Watch Winder Functionality:
Watch winders are designed to mimic the movement of the wrist, rotating the watch to keep the mainspring wound. They are programmed with specific rotations per day (TPD) to match the requirements of the watch movement.

No Overwinding Risk:
Because of the slipping mainspring, the winder will not continue to wind the watch once it's fully powered. The mechanism simply stops adding tension and prevents overwinding.

Potential Issues with Low-Quality Winders:
While overwinding is not a concern, low-quality winders might pose risks like magnetization or excessive wear due to continuous, unregulated rotation.
Therefore, while manual winding of a mechanical watch can lead to overwinding and potential damage, automatic watches (and the automatic watch winder box designed to power them) are inherently protected from this risk.