Comment 10 for bug 1481536

I have the same issue as the OP on Ubuntu 15.10 Desktop AMD64. It spits out "cryptsetup: unknown fstype, bad password or options?" after the correct passphrase is entered then proceeds to boot normally. I thought it was just me, because I have a LUKS-encrypted LVM setup that might be different from what Ubuntu was expecting in a couple of ways.
1. I set it all up using the command line before going into ubiquity.
2. I set it up using the Ubuntu 14.04(.1, maybe) Desktop AMD64 LiveUSB over a year ago. (I did format the partitions containing / and /boot when installing 15.10.)

In case they help, here are my fstab and crypttab with comments removed:

/dev/mapper/kryptvg-root / ext4 errors=remount-ro 0 1
UUID=3a58960b-caa8-4573-8730-812bba9b0a69 /boot ext4 defaults 0 2
/dev/mapper/kryptvg-data /data ext4 defaults 0 2
/dev/mapper/kryptvg-swap none swap sw 0 0

krypt /dev/sda3 none luks