Problem: Left mouse button releases when held down. It makes drag and drop fail, among other things. In my case, both buttons ceased working after a while. Fix: ""Press the right click button and hold-it, turn the mouse off and on, leave the right mouse button pressed while clicking on the left click button 5 times Quit pressing the right click button and turn the mouse off. Click and hold the right mouse button, turn the mouse on and finally release the right mouse button." As the original poster of this said, it works!!!! Note that this is happening in 2020, the year of Coronavirus This is really unbelievable, but it must be a reset sequence pursuant to some other arcane sequence that messes it up in the first place. This is a fix for the Logitech Performance MX mouse, but may work for others.