Is my SD card broken?

I have a Late 2012 Mac mini running Yosemite 10.10.4. My digital camera takes 4GB micro-SD cards and I import my pictures into the Photos app using an adaptor card to convert from microSD to the normal size. I would like to share some pictures by copying them back onto the card, but whenever I try this using Export in the Photos app, it warns ‘Export Complete with Errors’ and ‘Could not write file to destination (1,016)’. I’ve been advised to reset the PRAM but this doesn’t seem to have helped. Judith Harvey That error is because the SD card is read-only and I think this is much more likely to be a hardware problem. Does your SD card adaptor have a little slide on one edge (usually labelled ‘lock’)? If so, and even if it is currently not in the lock position, this may be the cause. SD adaptors are very flimsy things – little more than some thin gold- plated contacts sandwiched in a plastic envelope. The write-protect lock doesn’t change the electrical connections on the card itself in any way. It’s just a little bit of plastic that slides back and forth. The card reader in your Mac detects this with a spring-loaded contact that fits into the tiny slot. Sometimes this gets stuck and the Mac thinks the card is locked. Blowing a can of compressed air into the slot might free it, otherwise you’ll need to open up the mini and gently prise the contact free.