I have a similar problem. Since the last update Enpass kept crashing or shutting down and since this morning won't accept my master password anymore, it keeps telling me that the password is incorrect. But I have never changed the password and am 100% certain that I am typing the correct password. Also downloaded and tried the version 5.6.1 mentioned above, same story. Any thoughts on what I can do or try?
Working on a MacBook Pro running on macOS Sierra 10.12.6 and 2,9 GHz Intel Core i5 Processor.