Thank you for answer to me SurferTim,
There is just one file in 8.3 format name.
As I wrote, I change the MEGA to be sure that the problem can't be imputed to it.
I think that it will be funny to write an answer
to the scrolling question in your scrolling texte
Thanks too for your answer Fat16Lib,
The 64MB sd card is marked "Multimedia card", so... I think its an MMC...
Thank you for all these tips.
I formatted the cards with SDFormater V3.1. I'll try SdFat and post the results.
it is certain that writing a library as SD.h is a big job. Successful work indeed! Admittedly, this is a big library for a card Uno but perhaps it could be made more efficient for the more powerful cards, such as MEGA and those that will probably come out in the coming months or years...
Are you the author of this library? I think I read somewhere your username !...
anyway, thank you very much