SiaPrime allows for local passwords for a seed to be set. By default the password will be the seed. If a custom password is set, it may not be saved through version updates, so try the seed again.
You may notice the seed and password are (by default) identical; this is expected behavior. SiaPrime allows users to create an easy to remember passphrase distinct from the seed, but the seed is the true password and the only way a user can recover a wallet in the case of corruption of wallet loss or on a different installation.