What if the data does not fit on my Navionics+ memory card?
If the Chart Installer program is not allowing you to proceed with a download because your Navionics card is full, you can purge the card of charting information to make room to download the areas you specifically intend to view. You can find instructions to purge your data here: Purge Coverage Areas with Navionics+ or Navionics+ Updates
It might also be that there are files on the card that are not supposed to be there. You can open the card on your PC and check it for any non-Navionics files. (for example, a plotter software update file.) Removal of these files will resolve this issue as well.
Navionics files: Eligibility Config NTag Warnings & acknowledgement folder named NAVIONIC (numerous files and folders inside)