After download data from my shuttle, i see a "header error" while opening a file.

There are rare circumstances when using Onset optically-coupled loggers (those that operate with the BASE-U-4 Optic Base Station and U-DTW-1 Waterproof Shuttle), where the logger header may become corrupted (the logger header includes vital information about the logger and deployment). These circumstances include the momentary interruption of communications during the launch sequence and can result in a “Header Error” message being displayed by HOBOware when trying to plot the data. Using the “Force Offload USB Logger” feature in HOBOware , the data normally can be recovered and sent to Onset for retrieval.  However, if the logger was offloaded and relaunched with the U-DTW-1 Water Proof shuttle, this corrupt header will remain in the logger and this error message will be displayed on subsequent offloads.
It is therefore suggested that, if you offload a data logger with the shuttle and, upon opening the file in HOBOware after offload you receive a “Header Error” error message, that the logger be relaunched directly from a computer the next time it is deployed.   This enables HOBOware to replace the corrupt header with a correct header (as the shuttle cannot do this for you).