Version Information

C
AUSE
:
 
 
 
The file system on the TrueCrypt volume may be corrupted (or the volume is unformatted). 
P
OSSIBLE 
S
OLUTION
:
 
 
You can use filesystem repair tools supplied with your operating system to attempt to repair the 
filesystem on the TrueCrypt volume. In Windows, it is the ‘chkdsk’ tool. TrueCrypt provides an easy 

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111 
way to use this tool on a TrueCrypt volume: First, make a backup copy of the TrueCrypt volume 
(because the ‘chkdsk’ tool might damage the filesystem even more) and then mount it. Right-click 
the mounted volume in the main TrueCrypt window (in the drive list) and from the context menu 
select ‘Repair Filesystem’. 
P
ROBLEM
:
 
 
 
When trying to create a hidden volume, its maximum possible size is unexpectedly small (there is 
much more free space than this on the outer volume). 
P
ROBABLE 
C
AUSES
:
 
 
 
1. The outer volume has been formatted as NTFS 
2. Fragmentation
3. Too small cluster size + too many files/folders in the root directory of the outer volume. 
P
OSSIBLE 
S
OLUTIONS
:
 
 
Solutions Related to Cause 1: 
Unlike the FAT filesystem, the NTFS filesystem always stores internal data exactly in the 
middle of the volume. Therefore, the hidden volume can reside only in the second half of 
the outer volume. If this constraint is unacceptable, do one of the following:
• Reformat the outer volume as FAT and then create a hidden volume within it. 
• If the outer volume is too large to be formatted as FAT, split the volume to several 2-
terabyte volumes (or 16-terabyte volumes if the device uses 4-kilobyte sectors) and 
format each of them as FAT.
Solution Related to Cause 2: 
Create a new outer volume (defragmentation is not a solution, because it would adversely 
affect plausible deniability – see section Defragmenting).
Solution Related to Cause 3: 
Note: The following solution applies only to hidden volumes created within FAT volumes.
Defragment the outer volume (mount it, right-click its drive letter in the ‘Computer’ or ‘My 
Computer’ window, click Properties, select the Tools tab, and click ‘Defragment Now’). After 
the volume is defragmented, exit Disk Defragmenter and try to create the hidden volume 
again.
If this does not help, delete all files and folders on the outer volume by pressing 
Shift+Delete, not by formatting, (do not forget to disable the Recycle Bin and System 
Restore for this drive beforehand) and try creating the hidden volume on this completely 
empty outer volume again (for testing purposes only). If the maximum possible size of the 
hidden volume does not change even now, the cause of the problem is very likely an 
extended root directory. If you did not use the ‘Default’ cluster size (the last step in the 
Wizard), reformat the outer volume and this time leave the cluster size at ‘Default’.

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If it does not help, reformat the outer volume again and copy less files/folders to its root 
folder than you did last time. If it does not help, keep reformatting and decreasing the 
number of files/folders in the root folder. If this is unacceptable or if it does not help, 
reformat the outer volume and select a larger cluster size. If it does not help, keep 
reformatting and increasing the cluster size, until the problem is solved. Alternatively, try 
creating a hidden volume within an NTFS volume.