Yesterday I was sailing with my GPS. When I tried downloading the results from the memory card I found the file was empty.
Looking at the settings on the GPS I went to the Memory Card menu. This menu has changed on the GT-11. The menu only has four entries, Log Switch, Min Speed, NMEA Items and File Size.
I am pretty sure there were other entries such as Format Card and something else. The GT-11 was working fine a few months ago. I've tried two other SD memory cards and it didn't make any difference. All three cards work in my laptop's card reader.
Any ideas how to fix the GT-11?
Edit:
I checked the firmware, its V1.61 (B0608T) I upgraded to this firmware shortly after buying the GT-11. I checked the manufacturers website and its the current firmware.
When you turn it on does a message come up that says "card found".
If not you may not have the card inserted incorrectly or its faulty.
I just tried turning it on with no card inserted.
It switches on with no message. I think it used to complain about no memory card before. So perhaps there is a setting on the GT-11 thats not right?
I just checked SD/MMC in the data logger menu. It says no card found when a card is inserted.
Moby, I just experienced the exact same issue you are describing!
Turns out I had accidentally switched on the write protection on the card. Check your memory card...if it is in the 'Lock' position it won't record jack and the menu on the GT-11 won't have options for 'Format Card' or 'Remove Card'.
When you normally insert a memory card, does it sort of lock into place? Mine has never done that though I think I read in the manual it should. However when I closed the bottom flap I guess it pushed the memory card up into place. Is that normal operation?
If I recall correctly, when turning the GT-11 on, normally it says something like Memory Card found. Mine isn't doing that.
I tried the locking mechanism in both positions but its not making any difference.
The card feels spring loaded. The lid pushes the card in when you close it. Have you tried updating to the latest firmware? If you've tried a few other sd cards, it sounds like a GT11 problem, not the card. Is it still under warranty?
Thanks for that Shear Tip and Stribo.
I have established the problem based on your information. I was not pushing the memory card far enough in, so it was being pushed in by the lid when closing. However this has pushed the rubber coating. So now the rubber coating will not push the memory card far enough in.
However I pushed the card in further and it clipped into place, solving the problem. Thanks again! 
Pointman, I found that if the card is read only, it will be recognised by the GT-11 when it starts up but then there is no further action. Thanks for the info too.
