postado como resposta para permitir a formatação ...
Você tentou o utilitário LaCie?
extrair do pdf de instalação
- Before using your drive, LaCie Setup Assistant software must be launched to format your drive. It will:
• Optimize your drive according to your needs
• Copy the manual and utilities onto your drive.
To launch LaCie Setup Assistant:
Windows users: Double-click the LaCie drive icon in My Computer/Computer.
Mac users: Double-click the “LaCie Setup Assistant” icon on your desktop.NOTE: If you do not launch LaCie Setup Assistant or if you quit LaCie Setup Assistant after the formatting has begun, your drive will not be ready to use and will require manual formatting. The user manual and utilities will not be available on your drive and will have to be downloaded from the LaCie website: www.lacie.com.
NOTE: Running LaCie Setup Assistant does not prevent you from using your computer’s native disk utility program to format or partition your LaCie drive. Simply follow the Setup Assistant through completion, then use your computer’s native disk utility (Disk Management for Windows or Disk Utility for Mac) to reformat your drive.
A última parte é preocupante, no entanto. Seja qual for o problema, ele está fazendo com que o sistema pense que a unidade é somente leitura agora.