Factorio Forums

1/2) During game play mouse will start drifting up and to the right randomly. Drifting stops when shifting focus to another program. Drifting resumes when factorio is refocused. When I exit factorio the drifting continues for about 2 seconds before stopping. Restarting Factorio causes the drifting to occur starting from the loading screen, and the motion is in sync with the loading bar progress. The drifting motion stops for the few frames when the loading bar isn't moving. Restarting the computer temporarily fixes the drift. Once the drifting starts rolling back to an earlier version of factorio doesn't fix it. The drift on startup persists if I roll back to an earlier version of .17 and even the .16 stable. Only clears when starting factorio after a PC restart.

I'm not able to consistently reproduce the conditions to start the drift. I've tried using a different mousepad. I've tried running the game with most of the other other programs on the PC closed (discord, slack, chrome, logitech controller profiler, etc.) and the bug persists. I've checked that my keyboard is not producing any spurious inputs. The only gameplay correlation I can think of with gameplay is this started right around the time I began scaling up my logistics network and started having large power fluctuation.

3) Expect mouse to not drift across the screen with no user input.

Attached is the log file and the save i've been recently playing and noticed this in.

For me (working in electronics and programming) this sounds more like electrical interference. Something like: High CPU usage -> high power demand -> high ripple on power lines. This propagates by wire to mouse (from gpu and cpu i assume this is stationary pc) and by coincidence this ripple in power supply makes optical sensor in mouse to detect some spurious movement. This can be easily tested: run factorio, move coursor to lower left corner (as it is moving top-right) and just unplug mouse. Factorio should not be able to detect that mouse is disconnected, but if cursor stops moving, then issue is within mouse itself.

Yeah thinking about this more this sounds more like a local hardware issue than a bug. Feel free to close topic.