Have you tried deleting both parts of the game data? The save data is separate, so it will not be deleted.
Under the 'game' menu on the XMB press the up arrow until you see the "Save Data Utility (PS3)"; press X on that option then press triangle on the GT6 save data. Then 'copy to USB' or external device (can't remember the exact phraseology...).
An important addition to that, that could just save one's a$$. Take that USB stick and copy and paste that backup file to your PC or other device. Reason is, if you continue to use the USB to back up, each new successive backup overwrites the old one and it's gone. If your new backup happens to be corrupted, you won't know until you need to use it and if it's your only back up, you're up the creek without a paddle. I back up every second or third time I play and after every update and any time I tune cars just to be safe. You'll have to change the name of the file on your PC to make each backup a unique filename, but if you need to use them to reload your saved data, you have to change the filename back to the original name.
No idea, Google is your friend. Bash it in, you won't be the only one!
