| Possible Cause ||This could be because your Logger data retention and Historical Data Server backup schedule are not in sync. You should plan these two schedules together so that you retain data on the Logger for the period in which the HDS is not backed up. For example, if you are retaining data on the Logger for 2 weeks, you should back up the HDS, at the minimum, once every two weeks. This way, if the HDS fails, it can recover past data up to the last two weeks from a previous HDS back up and data for the last two weeks from the Logger. If you are backing up the HDS every two weeks but storing data on the Logger for only a week, you will be missing a week of historical data if the HDS fails or the database has become corrupted.