This bug occurred for me with a fresh installation of Ubuntu 19.04. I created a new installation of Ubuntu 19.04 on a empty disk and checked the box to encrypt the installation. After the installation I tried to change the password and got locked out.
This is the output of sudo cryptsetup luksDump /dev/sda3 after the failed attempt to change my password: LUKS header information Version: 2 Epoch: 4 Metadata area: 16384 [bytes] Keyslots area: 16744448 [bytes] UUID: 233e3965-3d97-4619-969e-ab9ef9b379d8 Label: (no label) Subsystem: (no subsystem) Flags: (no flags) Data segments: 0: crypt offset: 16777216 [bytes] length: (whole device) cipher: aes-xts-plain64 sector: 512 [bytes] Keyslots: Tokens: Digests: 0: pbkdf2 Hash: sha256 Iterations: 37406 Salt: ec 30 aa 1b 97 ef d1 a5 fb b4 1f ba 58 a9 f6 6d e9 d8 c4 73 b4 1b b9 c0 52 ff bf 2f e9 93 d8 47 Digest: f3 dd bb 32 f3 69 45 26 76 86 9a c4 4c d4 41 d4 67 bc f1 10 b3 65 87 d6 3b 51 1d 52 f1 d6 1d 9f -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1790979 Title: Unable to change disk decryption passphrase To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-disk-utility/+bug/1790979/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs