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I can't mount a encrypted SD card with Truecrypt anymore.

mount: wrong fs type, bad option, bad superblock on /dev/mapper/truecrypt1,
       missing codepage or helper program, or other error
       In some cases useful info is found in syslog - try
       dmesg | tail  or so

Usually if this happens to a normal partition, runing fsck on it will solve my problems. But what do I do with a encrypted partition?

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This looks so much like when I try to mount my USB (not encrypted). What do you get from dmesg? – phunehehe Nov 12 '10 at 16:36
up vote 4 down vote accepted

To create the /dev/mapper/truecrypt1 device without trying to mount the contained file system, do this (replace /dev/sda1 by the SD card device):

sudo truecrypt --filesystem=none --slot=1 /dev/sda1

To confirm that there is still readable data to be found, you could first do something like this to look for text content (hit ctrl+c to stop):

sudo cat /dev/mapper/truecrypt1 | strings

Assuming the /dev/mapper/truecrypt1 block device has been successfully created, you can run normal tools like fsck on that device.

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/dev/mapper/truecrypt1 is not there when the error pops up. I assume it is removed again... – Stefan Nov 12 '10 at 14:41
@Stefan: I've added instructions to create that device now. – Wim Coenen Nov 12 '10 at 15:18
perfect answer. +1 – Stefan Nov 12 '10 at 20:30

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