<https://www.w7forums.com/threads/corrupt-lost-data-on-external-hdd.17127/>
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"Hi,\n  \n\nFirstly sorry for the long post but i thought i'd give as much info as possible..........\n\n\n  I recently purchased a Barracuda ST3000DM001 HDD for use as storage within an external Thermaltake 5G USB3 enclosure.\n   \n  I connected it directly to one of my PC's and installed Win 7 (32bit) onto a 1.4TB partition with the remaining space partitioned up to the 2TB limit, therefore making the partition approximately 600GB; (I was not aware of the limits at the time!!!), to be used as a data with no operating system installed. The remaining data above the 2TB limit did show up within the Disk Manager!\n   \n  I transferred all of my data onto the drive and decided then to do a fresh install of Win 7 on all of the other drives.\n   \n  Once I had done this I connected up the external HDD only to find that the data could not be accessed; Win 7 was saying that the HDD needs formatting.\n   \n  I then tried it on a different PC with the same results.\n   \n  I also tried it within a Startech USB2 enclosure and directly connected to SATA (on two different systems) all with the same results in addition to trying it on a Win XP system.\n   \n  One thing to note that the 3TB HDD DID boot several times prior to the HHD’s being reformatted and reinstalled with Win 7; I only checked the data was there, I did not check that anything was corrupt at this point. The fact that it started and everything was present without any obvious errors was enough at the time (hindsight’s a wonderful thing!!).\n   \n  Finally I have used Get Data Back (GDB) software to try and recover the contents, which I was able to partially do but there seems to be extensive corruption with many files unreadable. I am currently running GDB under XP (it takes 30+ hours!) having already run it under Win 7; just to try and see if there are any different results obtained.\n   \n  I have also tried Recuva and Panda Recovery which neither work as they both claim that the drive needs formatting.\n   \n  An extremely curious issue is that within the photos that are recovered via GDB, many of them are not the original photos but the same photo four times (but not always!!) i.e. the correct photo on the first file and then three copies of the same photo BUT with the original (correct) file name. Also the preview image of the file when going into is quite often incorrect; corrected by deleting the Thumbs.db and then refreshing though.\n   \n  The same effect has happened with my MP3 files; the song playing matches the track name but then the same song for track 2, 3 and 4; again with the track name being the correct one. Then it starts again with song 5 matching the track name but then track 6, 7 and 8 still showing the correct track name but upon opening playing song 5.\n   \n  Excel files upon opening are, generally but not always, not the files that they should be but a different file maybe that was next in the list or nearby, with many being corrupted.\n   \n  The files contain accounts data for a friends company so are rather important; as are the personal photos.\n   \n  I do have some backups (made with Genie Backup) and these were moved temporarily onto the 3 TB drive (hindsight again……..) for the short time that I formatted the other drives.\n   \n  It will take a long time to sort through the current files and the backups (the ones that haven’t become corrupted), to find what is and isn’t useable; and I know that some of the data is older than the current data that has been lost.\n   \n  Please can anyone advise what can be done to safely recover the data."
<https://www.w7forums.com/threads/corrupt-lost-data-on-external-hdd.17127/>