If you are transferring your Micro SD card from another phone, DO NOT reformat your card... yet. Your phone may be experiencing a little difficulty reading the information. Your files should still be accessible via USB on your computer. Retrieve the info by accessing the drive the USB is plugged into, and then back up up SD card's info. You can reformat at this point if you want. From here, you can slowly bit-by-bit upload the files you want on the SD back onto it, while often checking to see if the error recurs.
From here you should be good.