sandisk ultra 32gb sdhc (SDSDU-032G-A11) writing error?

i  bought a sandisk ultra 32gb sdhc card (SDSDU-032G-A11) a week ago, and the first 4gb’s went fine but after copying another gb or so, it stopped writing, and the reader (sandisk micromate sddr-113) would shut off and stop working, and sometimes also locking up windows until the card was removed

so i returned it and got another of the same card today, and this time after about 6gb, it’s doing the same thing, i tried it in my camera (canon powershot) and when i try to take a picture with it, after a little while it’ll say 'memory card error on the screen

it can read and copy all the data off the card just fine, though trying to delete anything lock sit up the same way as copying to it

so i guess what i’m asking is did i just get unluckly with two bad cards in a row, am i using the wrong card reader, or does this card have know issues? i’ve used sandisk cards from 2gb to 16gb and never had an issue with them

most likely gonna just return it again tomorrow, though now i’m not sure if even a normal 32gb card would be ok to use or if i should just stick to 16gb for now