On x86_64 with the latest 2.6.18 kernel from FC5 updates, I was able to build truecrypt with no problems. (2.6.18-1.2200) With same latest kernel on i686 FC5 system, I get this error when trying to load the truecrypt kernel module: insmod: error inserting '/usr/share/truecrypt/kernel/truecrypt-2.6.18.ko': -1 Invalid module format FATAL: Error inserting truecrypt (/lib/modules/2.6.18-1.2200.fc5smp/extra/truecrypt.ko): Invalid module format truecrypt: Failed to load TrueCrypt kernel module Anyone know what the heck causes this? Is the latest gcc from FC5 updates incompatible with the gcc used to build the kernel? (I know it isn't the i586 versus i686 bug some have run into, I definitely have i686 versions of everything).