When you format ,you can still experience the issue and if that happens than you have a damaged sd card ,this same problem came up on my old wildfire with a bad sd card from ebay .
Sent from my HTC EVO 3D X515m using XDA
??? This doesn't mean you have a bad sdcard at all. I had this issue many times after mounting my phone to PC. I fixed by lowering the read ahead speed / eliminating a corrupt file on sdcard ( this could be any file,run a disk check whilst mounted to PC) I also only mount from recovery now and have not had the issue since.
sent from Willy Wilderbeast