He had trouble mounting it on his system because of a duplicate UUID - this doesn't mean that the filesystem was broken. As Arnavion wrote: > Since you say it'

He had trouble mounting it on his system because of a duplicate UUID - this doesn't mean that the filesystem was broken. As Arnavion wrote: > Since you say it's an external USB drive, perhaps it disconnected and reconnected uncleanly and the kernel thought there were two of that drive connected at the same time.