Sd card started showing up blank.

[AC Question]

Replaced with new sd card, same problem.

 

[B. Diddy]

Welcome to Android Central! Which phone? Did you get these cards from the same place? Although it's unlikely that two consecutive cards would be corrupt, it is possible that both of them are counterfeit, especially if you bought them from the same place. If the phone actually detects the card, run SD Insight to see if it's valid.