Why does e2fsck fail during boot, but not later?

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http://unix.stackexchange.com – When booting my server running debian, I'm presented with the following error concering my external hard drive: "/dev/disk/by-label/elements: The superblock could not be read or does not describe a correct ext2 filesystem. .... .... fsck died with exit status 8. ... ... A maintenance shell will now be started. CONTROL-D will terminate this shell and resume system boot." The thing is that if I enter ctrl-d or enter the maintenance shell the disk is correctly mounted and calls to e2fsck /dev/disk/by-label/elements reports no errors. This is very annoying since I need to type ctrl-d everytime (HowTos)