TrueCrypt can't fill outer volume with data

Discussion in 'encryption problems' started by Ralph_M, Dec 21, 2014.

  1. Ralph_M

    Ralph_M Registered Member

    Joined:
    Dec 21, 2014
    Posts:
    2
    Hello,

    I have encrypted my external 4 TB WD harddrive using Truecryt in Windows 7 x64, outer Volume size 3.6 TB FAT, hidden volume size 2.4 TB NTFS. The cluster size during the creation wizard I left as "default". When copying files to the outer volume, after it is filled with ca. 55 gb, truecrypt thorws the error that it prevented content being written to the hidden volume and locks down the drive. I've checked with Defraggler, the clusters being used are the ones at the start of the drive. With more than a whole TB of free space left on the outer volume I cannot figure out what the source of the problem is.

    In case it helps , I am not able to securily mount the outer volume under linux as I get the error that

    "The drive uses a sector size other than 512 bytes
    Due to limitations of components available on your platform, partition/device-hosted volumes on the drive can only be mounted using kernel cryptographic services."

    In Windows i can securily mount the outer volume without any problems... except the one I described at the start...

    To rule out hardware problems I've tried the same setup on another harddrive of the same model, with the same outcome.

    Any help will be very much appreciated as research on this topic yielded no result and at this stage I can't really use the drive.

    Thank you very much in advance,

    Ralph
     
  2. syrinx

    syrinx Registered Member

    Joined:
    Apr 7, 2014
    Posts:
    334
    I'm surprised it let you create a fat file system of that size in the first place. Anything over a few hundred GBs and I've always used NTFS but I can't recall exactly why. (been about 5-10 years since I used fat on anything but a small thumb drive) I thought FAT had a much smaller threshold than even 1TB but I could be wrong.

    I know the 3 different FAT file systems have different limits: fat, fat32, and then exFAT as the newest and broadest but I still don't know each ones limits.

    I'm sure someone with a better idea of the file system differences will come along but if not I'd suggest recreating it as NTFS on the outer container as well....
     
  3. Ralph_M

    Ralph_M Registered Member

    Joined:
    Dec 21, 2014
    Posts:
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    Thanks for your answer syrinx,
    During the creation process there was only a choice between FAT and NTFS, in the truecrypt documentation they write that it automatically chooses between FAT12, FAT16 or FAT32 depending on the number of clusers.

    The MS-guys say the max size for FAT is something like 8TB, given one uses 32KB clusters.
    https://support.microsoft.com/kb/184006/en

    At first I also wanted to use NTFS however truecrypt hinted that NTFS stores internal data exactly in the middle of the partition, hence the maximum size of the hidden volume can only be half the size of the outter volume and recommended to use FAT. As I would need more than half of the drive for the inner volume, FAT seems to be the only way to do it :(
     
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