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I have a Western Digital hard drive that's about 4 or 5 years old. It's 500 GB, USB. I use it to backup my Mac every so often. I had it partitioned: 1 side for full backups, and the other side for general storage of music, installers, etc.

I decided to get rid of the partition today and dump all the data. So I opened disk utility, and hit 'erase'. It started thinking and then disk utility crashed. After the crash, the hard drive won't mount, however disk utility still sees the drive, but not the individual volume within.

I tried booting up Disk Warrior and no luck there either. It has the drive as an "unknown drive". When I hit rebuild, it goes through all it steps and then stops cause of this error:

The drive "unknown" is severely damaged and DiskWarrior is unable to determine its case sensitivity

What can I do at this point? There isn't any physical damage to the drive. Never been dropped or anything.

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Is there anything on the drive you still need to retrieve? Or would running a fresh backup solve your current issues?

If nothing is on it you can't simply rerun a backup of, then forget diskwarrior and reformat the drive. If, however, you have unique files on the drive and require them I would suggest running a long generic test using Seatools from If it fails, it may be time to enlist a pro like myself to aid your efforts. If it passes, I have posted a simple article nearly a year ago that explains the use of a slightly more advanced recovery program from Stellar. It's not perfect but garners the best results of any publicly available Macintosh data recovery program I've come across in recent years.

Let me know how you make out, or reply if you have further questions.

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