Playstation.com Japan has released an announcement on a free space issue of Sony’s Memory Stick PRO DUO. This issue affects model MSX-M1GST, MSX-M2GS and PSP-MP1G.
The problem happens when you format your memory stick to initialize it. The free space might be less than the designed value. In this situation, you will not be able to save as much data as the designed volume.
To resolve this problem, you need to re-format you memory stick once more. Please note all the data stored on the memory stick will be lost when you perform formatting. Make sure you backup all the useful data from your memory stick before formatting.
Design Volume of the Memory Stick PRO DUO:
MSX-M1GST: 940MB or more
MSX-M2GS: 1850MB or more
PSP-MP1G: 940MB or more
If you are unable to fix this issue by yourself, please contact Sony Tech Support.
This combined with the higher transfer rates of the SanDisk is more than enough reason to stick with SanDisk in my opinion. However, for those of you who have the Sony sticks, this is something to be aware of.