Good morning,
I received the following error after updating to 4.1. "Failed to execute post processing commands". This occurred when exporting gcode to my sdcard. It took me a while to figure out that the sdcard had become locked (physical switch on the side). The error in Simplify3D is a little ambiguous. I think a future version should update that error message to make it easier for users to troubleshoot.
Thanks,
David