style="BACKGROUND-COLOR: #000000"I also have a Z3 and a 512 MB Sandisk . The camera is well protected against interference ( unless there is an EMP from a nuclear blast) so I do not think that the computer has something to do with the problem. Try using another memory with bigger capacity than the factory 16 MB that you tried . How old isyour 256mB card ? All flash memories (SD included ) wears out. They can also develop bad sectors just like harddisks and diskettes, it is proportional to the number of read write operations.