Not enough space to create hidden volume - but there should be

[Anonymous]

Hi,

I have a 1Tb external disk I'm trying to create a hidden volume on. The wizard gets as far as encrypting the drive as an outer volume but when it comes to creating the hidden volume tells me there is not enough space. I have about 34GB of files in the outer volume, so there should be more than enough space left for the hidden one (I need about 10Gb).
I've tried some of the troubleshooting tips such as mounting the outer volume and defragmenting it but only get about 37Mb of space available. If I delete all the files from the outer volume VC tells me there are 3.37Gb available?! That's on a disk with 931GB free!
I have reformatted the drive (no quick format) and re-encrypted several times to no avail and have run out of ideas.

Any suggestions as to what I can try to solve this?

Many thanks,

a paranoid humanoid

[Enigma2Illusion]

To maximize the outer and hidden space available for use, ignore the prompting of the GUI to copy non-sensitive files in the outer volume when prompted during the initial formatting. This will allow you more space for the hidden volume.

The issue is when using NTFS format stores internal data in the middle of the outer volume. However, in my tests, it appears to store internal data in the middle of the remaining available outer volume space. Hence, this is why the hidden volume does not have have the available size you thought should be available.

After the volumes have been created with empty outer and hidden volumes, then you can copy data to the outer (protect hidden volume) and to the hidden volume.

[Anonymous]

Thanks for your quick reply.

I have always used FAT as recommended by the VC wizard to avoid this issue.

I understand your suggestion about creating the hidden volume before copying data to the outer volume. But I still only have a maximum of 3.39 Gb available for the hidden volume. Is there a technical limitation why that can't be more (on an empty disk of 931Gb capacity) or am I doing something wrong?

thanks again for your help.

[Enigma2Illusion]

What size did you specify for the outer volume?

[Anonymous]

I encrypted the whole disk so i have 931GB in the outer volume.

I have actually managed to copy the files I really needed to the hidden volume now, it's 3.2 Gb. But I still would like to understand why VC wouldn't create a bigger hidden volume despite so much space available.

[Mounir IDRASSI]

There are no such limitation: a hidden volume can be of any size, the maximum value being dictated by how much free space is left by the outer volume.

I have just done a test using a 1TB drive and I was able to create a 900 GB hidden volume. Both Outer and Hidden volumes were formatted using FAT.
Below are screenshots that show this:

The algorithm that calculates the maximum allowed size scans the FAT map to find the maximum free space at the end of the outer volume. In normal cases, using FAT, data is copied at the beginning of the outer volume by Windows and free space is left at the end.

In your case, you always have a 3GB maximum size for hidden volume, this means that something in your PC is writing data at the end of the outer volume. It can be Windows (very unusual) or it can be a malware or any unwanted program (probable).

In all cases, there is something in your PC that is writing data without your knowledge.