When a height file contained a duplicate entry the following error message was printed to the log: ´Duplicate entry for markerID=...´ (PeTrack crashes, with this occurence) Suggestion: Change to ´Duplicate entry found in height file for markerID=...´ (+ ´PeTrack does not know what to proceed with´?) For discussion: - how about changing code to automatically take the first entry and printing a warning instead, in order for petrack not to crash?