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I am trying to set up a TrueCrypt hidden OS with as much space available in it as possible. I have a 100 GB hard drive which I have partitioned into a 10 GB C: drive with windows installed and a 100GB second partition. I created a TrueCrypt Hidden OS and copied about 15 GB of data to the Outer volume. I formatted both Outer and Inner as FAT32. I expected that the Hidden volume would be nearly 85GB, but when I was finished it was only 10GB just like my C: drive, and I am now unable to use most of my 100GB drive.

What am I doing wrong? I didn't see any settings for the size of the hidden OS. How do I create a Hidden OS with more hidden storage space than the decoy OS?

Here is a screenshot of the partition layout:


C: will be the decoy OS. E: will be the Outer Volume. I want a hidden OS inside E that is greater than 9.54 GB.

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The container is only 20GB so the operating system installed within the container ( the hiddne partition ) is only 20GB. You would have to provide more space for the hidden partition if you wanted more space. – Ramhound Jun 17 '13 at 12:19
I'm not sure what you mean @Ramhound. The outer volume is 100 GB. TrueCrypt is making the Hidden volume 20 GB to match the system partition, but there is a lot more space available. How do I provide more space as you suggest? – user231750 Jun 17 '13 at 12:23
You said you made a 20GB partition. You need to extend that partition if you want more space. – Ramhound Jun 17 '13 at 12:59
That's the decoy OS partition. SO you're saying that the answer to my question is, "You can't, the TrueCrypt Hidden OS volume must be the same size as the first partition, the decoy OS partition"? – user231750 Jun 17 '13 at 13:02
Can you provide a screenshot of the layout of your actual hdd for us? Just post the link I will add it to your question. – Ramhound Jun 17 '13 at 13:09

It seems my message is too late, but I drop it anyway. TrueCrypt hidden volume by definition is always equal system volume. It cannot be changed. Still there is way to use all your HDD space. You might create three partitions: first two for the decoy and hidden OS. Then you create HIDDEN TrueCrypt volume inside third partition and automount it when Hidden OS starts. In this volume you could keep “Program Files” or even move “User Profile” there.

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