Your Samsung Galaxy S III includes a Secure Digital card that contains all of your personal files and any third-party apps you've installed to your smartphone. The SD card has a limited capacity of 16 to 64GB, and once you reach that limit, you can't download or copy any more files to the card. To free up space on your Galaxy S III, you can either format the SD card, which deletes all its data, or delete individual files from the My Files app.

Format the SD Card

Step 1

Open Settings from the Home or Apps screen and then select "Storage" from the menu.

Step 2

Tap "Unmount SD Card" to prepare the card for formatting, and then tap "Format SD Card" from under SD Card.

Step 3

Press "Format SD Card" again to completely wipe all data from the card.

Delete Individual Files

Step 1

Open My Files from the Apps screen and then tap "All Files."

Step 2

Choose "ExtSDCard" from the options and then navigate to the folder containing the file you want to delete.

Step 3

Place a check mark in the box located to the left of the file and then tap the trash can icon. Press "OK" to confirm.