gentoo

i don't recomend this option cause it affects performance - i suggest enabling it for testing if the lack of crypto algorithm is the cause of your error (i had number 253 in my error but...) if it's the case then after enabling it everything should work (very slow though). if you can't mount volume despite enabling it your problem lies somewhere else (probably:P) i have compiled in the kernel (on my laptop), but if you can't reboot your system (without X -> i guess server) you can compile them as modules (device mapper as well) I came to this solution recalling old days when truecrypt was kernel module, and loading it required all other crypto modules loaded:) good luck

since you're gentoo user i guess you have your own kernel so 1) check whether you have appropriate modules compiled in kernel that is: <*>Device Drivers <*>Block Devices <*>Loopback device support ..... <*>Multiple Devices driver support (LVM and RAID) <*>Device mapper support <*>Crypt target support if you have all of these go to truecrypt>settings>preferences>system integration and check "Do not use kernel cryptographic services" if you have the same error (or maybe other now) 2) Check if you have all cipher and hash/digest methods used by truecrypt (and chosen by you) compiled in your kernel/as modules (then load them) these are: <*>Cryptographic API <*>XTS support <*>RIPEMD-160 digest algorithm |default for truecrypt <*>SHA384 and SHA512 digest algorithms |you can choose <*>Whirpool digest algorithm |sha512 and whirpool too <*>AES cipher algorithms |default truecrypt cipher <*>AES cipher algorithm (x86_64) -> if you are on such architecture or/and: <*>Serpent cipher algorithm <*>Twofish cipher algorithm <*>Twofish cipher algorithm(x86_64) it worked for me hope it helps but i'm disgusted by lack of ANY support for linux instalation (or linux support at all) on truecrypt home page... there are only methods how to use your system less useable (those hidden volumes, hidden systems etc. are overkill - if sbd would interrogate you - you would get skompolomine injection and told them not only passwords but some things you don't even know that you remember) that's why i posted this solution (usually i don't).