Connecting to a MySQL server with bad credentials fails with a misleading error message: "The Server at ... experienced an error or encountered bad or corrupt data" Instead "mysqld.err" log says: "[Warning] Access denied for user ..." Please, improve error handling and reporting in this scenario. Ideally, prompt again for user/password with correct heading message (this also means using a better face, like bold), f.i. " *** Access denied. *** Please try again Username: ... Password: [OK] [Cancel] "