Nuvi 260w reports SD device not ready unable to copy data

There is usually a small drive lock on the sd card that sometimes will move to the lockout position. This may well be your issue!

I looked at the card. The SD card was unlocked when I inserted it and failed to download. Any other suggestion?

There's probably an SD card diagnostic built into the Nüvi 260w (if it's like the others).

I don't own one, so don't know the details - but it's probably hold the "Time" or "Battery icon" for 5 secs and then hit "NEXT" until you find it. That should tell you whether the Nüvi itself can access the card.

Plugging the card into an external reader will help determine if it's the card itself.

If it's a pc use the explorer and see if you can access the card that way, you might try to format it, (the SD card). If it's like mine it will have a garmin folder on it. The poi loader or the gps makes the folder. So that should give you some kind of clue...

I put a blank SD card in my unit started the gps and then checked the card, it was still blank. I then loaded poi's to it using a card reader, the poi loader made the Garmen folder, with a poi folder in it, with the poi in the poi folder....

I also had a problem with a reader I have and a 4 gig SD card made by HP. A new reader resolved that problem.