I purchased a Lowrance Ifinder H2Oc and it came with a mapping card that includes over 2000 lakes across the U.S.  only problem is, when I put the card in and turn it on, nothing shows up.  No depth contours, no lake details, or anything.  It's like it doesn't know the card is there.  Is there something special I need to do to get it to read off the card?  Anyone else run into this?  Thanks in advance for the help.

1: read the directions

2: go to the lowrance site and look there.  

http://www.lowrance.com/en/Products/Outdoors/iFINDER-H2O-C/

You have to select the mapping card.  Go through the menu.

As stated above, read the instructions.

Wow, how dumb I am to not have just read the directions instead of asking a question.  HA, jk.  Let me rephrase my post.  I HAVE read the directions and tried everything else I can think of but when I go to select my GPS data to load, it doesn't find anything.  It says no MMS found.  I'm wondering if anyone else has ran into this.  The mapping card is a navionics hotmaps handheld edition.  On the navionics website it says it's compatible with the Ifinder H20 so I don't think that's the problem.  Any ideas?  

Mine works just fine and I use Navionics Hotmaps Premium South and East or free download Lowrance maps. I just insert whichever card I want to use and go thru the menu to tell the unit which software to read.

I dont know if you can, but maybe try to reset the unit?

That might help the unit to load the card.

Have you ever inserted the map card into a card reader?