Sony MSW-M2100 Operation Manual page 107

3
Press the F5 (SET) button.
Formatting is executed.
If you are using a new "Memory Stick", or if an error
occurs during execution of F3: FORMAT STICK, use
the sub mode to format the "Memory Stick".
Note
All data in the "Memory Stick" is erased when you
execute F3: FORMAT STICK.
Chapter 12 Setup Utility Menu Functions
12-3