I have a LaCie thunderbolt/usb 3.0 external HD that was working perfectly fine up until about two days ago, when my computer (running macOS) would no longer recognize the drive at all.
I don't get any error messages, the drive doesn't show up in DiskUtil at all.
If I check System Information (systemprofiler), a LaCie thunderbolt (or USB) device will be listed if plugged in, but it's not recognized as a storage location.
I have Windows 10 installed on another partition, so I booted that up and tried the drive, but Windows doesn't recognize the drive either (no error messages or anything). It won't show up in Disk Management, but it will show up in Device Manager.
Recovery software seems to be useless, and the drive isn't detected at all.
I booted PartedMagic, and the drive shows only up in the system information as a SCSI Disk with correct manufacturer details, but an error appears that reads "this device hasn't been claimed".
I do have a backup, so I'm slightly less concerned, but any help would be greatly appreciated to try to recover the drive.
Thanks
Best Answer
This happened to me many years ago. At that time I found to my surprise that a disk is detected or not by its stamp, found in the first few bytes in the first sector. If one of these bytes is corrupted, the disk is lost. This is called the Disk Signature.
At that time, I solved the problem by copying these bytes from a similar disk, but I really don't remember how many bytes I copied or using which tool.
I suggest that it would be better to use disk rescue tools to fix the first sector.
TestDisk might do the job, as explained in the article
How To Fix: External Disk Drive Suddenly Became RAW.
The NTFS Data Recovery Toolkit is another possibility, but others such products do exist.
For more information and some manual methods see :