Comment 20 for bug 1718658

Same as @stokito happened to me. Yesterday I upgraded to Kubuntu 18.04 via "do-release-upgrade" command from a previous install of Kubuntu 17.10 did some half a year ago. When I restart the system I see the Kubuntu Plymouth start screen but then it never arrives to the login screen (sddm). I can login normally in any of the tty's seeing my home correctly decrypted but with these errors:

Could not find key with description: [<key>]
Could not find valid key in user session keyring for sig specified in mount option: [<key>]
Error parsing options; rc = [-2]

Also tried the aforementioned workaround "ecryptfs-manager" but sddm doesn't start either. Also tried installing lightdm with no luck.