The extension .VMG refers to files of the type, Nokia text messages. The nokia text message files are used for storing the message text information in an organized fashion which is used by various services on the communications devices manufactured by Nokia.

The file structure of a VMG file is designed to store personal messages in the cell phones. The sms are text based only and the file structure stores the metadata along with the message in the form of headers and timestamps. The file also stores information in a null separated text format to save space on the device.