You may be experiencing any of these issues with your SD card:

• The SD card is not detected by your device.
• An error message shows when using the SD card.
• Slow file speed transfer to and from the SD card.

Follow this checklist to ensure best performance from SD cards you use with your phone:

• Check the SD card for physical damage.
• Check the SD card's class rating; use class 6 and higher (class 10 is recommended for best performance).
• Make sure that the SD card's metal teeth are clean.
• Make sure that the SD card has sufficient free storage for your needs.

To prompt the phone to recognize your SD card, follow these following steps:

1. Restart the phone.
2. Unmount the SD card from the phone.
   
   Android: Settings > Storage > Unmount SD card
   
   Windows: Settings > Phone storage > Remove SD card
   
   
3. Remove the SD card from the phone and re-insert it.
4. Open the SD card on another device, or on a PC using a card reader.
5. Format the SD card as FAT32 using a computer and re-insert it into your phone.
   NOTE: Be aware that formatting the SD card will erase all data on it. Before formatting, back up any data you wish to keep.