Lost all music on my Ipod after a sync

[tich27]

Hi,

After made a sync (asking for a back-up) between my I pod and spotify, I have lost all my music store in my ipod.

I have found a file name "storage" on my pc, but all of these file are not mp3

Could you tell me where this backup has been store?

How can I found my music?

Thanks for your help

Regards

Eric