The data was probably rejected because of the timestamp. The clock resets itself to 2000-01-01T00:00:00 – but then ModularSensors applied a negative offset to it assuming you wanted the file to be in UTC-6 with an RTC set in UTC. That caused a weird rollover (roll-under?) giving you a timestamp of 2000-01-01 252:211:00. MonitorMW would have rejected that time purely based on syntax (hours and minutes must be two digits). Obviously, the developer of ModularSensors did not do sufficient testing for this scenario. I’m sorry.