Playing with Faronics Deep Freeze pt 1

Hello all, and I’m back.  If only I were better than ever.

I guess this post could also be titled “making software do things the manufacturer didn’t intend”, but here goes:

The thawspace of Deep Freeze can be accessed (offline) with ImDisk (free, available here) and WinImage.  And of course with Linux (loopback device, lookup the man page for losetup).  We recently had a situation at my employer where the existing thaw space was no longer big enough, and critical system files (user profiles) were stored on it, so I researched how to create a new one – and it is fairly easy with those above tools.  Turns out the driver for the thawspace, named ThwSpace.sys, has some parameters in the registry at:


In this path, you’ll see a key for the drive where the image file is located (ususally C:), and a sub-key for the drive letter the thawspace is mounted on.  Under the sub-key, the default value will indicate how big the image/thawspace is supposed to be in megabytes, and there will be another binary value that I honestly don’t have a clue what the data in represents.  The name of the binary value will be the name of the actual image file used for the thawspace.

What’s cool is you can thaw deep freeze out, setup a disk image with ImDisk, and change the registry values for the ThwSpace service to point to your disk image, and voila you have a custom thawspace.  I highly recommend that you follow their naming convention for the thawspace image, though – usually it’s at C:\$Persis0.dsk or C:\Persis0.dsk depending on what version of Deep Freeze installed the thawspace to begin with.  I just added a new image, and ended the file name with a 1 instead of a 0.

What I did to solve our little situation was to create a new, bigger image with ImDisk, use xcopy to copy all the files with permissions intact, and change the registry to reflect the size and file location of the bigger disk image.  On the next reboot, the Thawspace driver mounts the new disk image instead of the old, and you can erase the old one.


6 Responses to Playing with Faronics Deep Freeze pt 1

  1. kyle says:

    This works and thank you for having a google friendly site, as opposed to the Faronics forums where I logged on where I normally gain access to downloads, and found NOTHING.

  2. Mauricio says:

    maybe you can help me i have a problem with a shut down and deepfreeze dissapeared now i cant access all my info on the Thawspace is there anyway to recover that data? or how can i extract or mount the Persis0.dsk

  3. heathparker says:

    Go get a copy of ImDisk from and use it to “mount” the persis0.dsk (thawspace). After ImDisk is installed, you should be able to simply find the file with windows explorer, right click it, and select “Mount as ImDisk Virtual Disk”. In the dialog that appears, you can select the drive letter, i usually also choose “Harddisk Volume” for the device type. Be forewarned, sometimes there is a long delay before the thawspace is accessible. This delay corresponds to quite a bit of drive access as well.

  4. Phillip says:

    Hi I my hard drive with the Thawspace recently wouldn’t boot into the OS. So I tried removing it and install the hard drive in another PC, then I tried the steps mentioned here and I can’t seem to mount it. I get an error message saying the file is corrupted and unreadable. I noticed that its not formatted but I’m afraid that if I format it I would loose all the data in it.

    • heathparker says:

      Unfortunately it sounds like the hard drive is going bad. See if you can make a backup copy of the thawspace file to another drive. It may give you the same error, if it does that means the drive (or at least the filesystem) is bad. Unless you want to send the drive off to a data recovery company, run chkdsk on the problem drive in the good PC, using the /F and /R options, and then try to mount the thawspace again.

      GOOD LUCK!

  5. Mike in ROC says:

    FYI I am now seeing the applicable registry key at HKLM\System\ControlSet001\services\FarSpace\Parameters\C:\

    I assume the C: indicates the host drive. The entries show the host file, size, etc. I do not see an indication of hidden status (I have a visible D: and hidden T:)

    Amazing this info was still applicable 8 years later! Thanks.

    – Mike in ROC

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