I am having consistent trouble with these SD cards (below).
About 5 of 7 write/verify cycles fail (or worse), for multiple new cards (>25 brand new cards tried). These are high reliability microSD cards, available from Digikey. So high confidence that there is not a problem with the card itself. Multiple SD to microSD adapters tried, as well as a different USB-SD interface.
Digikey part# 1582-1117-ND
Apacer Memory America
MEMORY CARD MICROSD 256MB SLC