May be i can add some usefull hints here. (for a newbie - cool :rolling: )
I exactly had this awfull pb with my ... ipaq 4150.
first thing it's may not be because of the pda
then it happened with a 1go sd. so i took the sd back and got a new one. And i tested it with a simple tech256 mb with wich i never had any trouble with (cost me 100 € 13 months ago !)
And with this it happened to !!
so my opinion:
may not be the pda,
may not be the sd card.
But, my be a combination of software working badly toogether.
the pb is i use dozen of software, who's guilty.
no evidence at all but i suspecting wishbar advance 2 - (this is totally subjective - not shure of it)
Hope i won't get this pb again !
sometimes nothing is left, sometimes empty files. or half of a picture - a total mess
Good luck with this !