I bought the card 8 weeks prior to and since receiving about 6 weeks prior to use. Since yesterday, the card is no longer recognized in my smartphone. It is now only displayed in all units have a capacity of 1 megabyte, but the card is not readable or writable. All data since the last backup are lost. Update August 29: After a very friendly contact with the seller Memory Man a replacement card was delivered promptly. This is for nearly three weeks in use, so far without any problems. Let's see if the replacement card proven.