Corrupt waypoints stored on NAVIONICS Chips, I know the unit shouldn't save to a Chart chip, but it happens and when it does the sync with an interlink along with the new waypoint software seems to be causing a problem. Put your chip in the computer, look for a file called MATRIX and delete the folder, this according to Navionics support. The rest of the story... I had several posts over the past month regarding problems with both my 997 and 1198 units going into a loading loop without being able to boot. The problem surfaced after updating to the most recent software updates. I was emphatic in my discussions with HB that I followed the update protocols and in fact used the units several times without an issue so the problem was not caused by improper software updating. Both units individually had to be taken back to a previous version just to get them to work again. As it happened, they both eventually locked up and back to HB they went as well as the interlink. They were both returned, and although HB lost the interlink, they replaced it free of charge with a brand new one that came with all the cables, sweet. So all back up on line and as I did before I cleaned up any duplicate waypoints and checked for and deleted any that did not have a valid coordinate or had a weird name... sort of looks like Greek symbols. Next thing I know I've got more corrupt waypoints, and where did they come from... I had inserted a NAVIONICS chip and as it loads I see it says, " Loading 0 tracks and 233 waypoints". Wait a minute these chips should have waypoints on them? Turns out, my unit was saving and using waypoints from a NAVIONICs Chip and that’s why I never saw them when I cleaned up my units hard drive and the SD. It is also why the units booted fine and then later on had a p[problem, the problem surfaced when I put my chart chip in to go fishing. My suggestion; take a look at your chips and make sure you are not loading waypoints and tracks onto the chart chip, you should be saving to the unit hard drive, interlink or using a blank SD for saving and managing tracks and waypoints and snapshots... just my thoughts.