I'm getting just one dataset per day (always at the same time) saved in the data file (1 Hz sampled data averaged over 10 min). So I have 10 min of data per day. System was installed 3 days ago, identical to several other systems at same site (all running with same program), none of which has this phenomenon (which I have never seen before either). The system most likely does run continuously because the record number increases by 144 from one dataset to the next. Battery voltage also fine. I suspect a logger error, although the system had been fine before being sent to site - if so, is it likely to be solved by reset, or should I rather make the (big) effort to send a new logger to the site before making the (somewhat lesser but still significant) effort of sending anyone there without a logger?