Deleting text messages from your phone's inbox will help free up storage space. However, you may accidentally delete an important text message while trying to get rid of old messages. If this happens, you can download a file- or data-recovery program on your computer and use that program to retrieve deleted files from your phone's memory card. Once the text message files have been recovered, they will be automatically restored to your phone's internal storage drive.
Turn on your computer. Connect your phone to your computer via the USB cable that came with the device or insert the phone's SD card into your computer's SD card-reader slot.
Browse online to find freeware data-recovery programs, including Recuva, File Recovery 4 and Smart Recovery 4.5. Download the program and save the file to your computer's desktop. Double-click the file icon to launch the file recovery program.
Choose your phone's internal storage drive or memory card from the file recovery program's drive selection menu. The program will display a list of files deleted from the phone's storage drive, including erased text message files.
Select the text message files you want to retrieve and click on them. Click the "Restore" button and the text message files will be restored to your phone's storage drive.
Disconnect your phone from your computer and disconnect the phone from the USB cable.