AMPS enforces unique client naming whenever there's a journal (transaction log) configured, and allows duplicate clients when there's no journal configured.
If you'd like to enforce unique client naming, but don't need a journal, there's a simple workaround. You can enable transaction logging without capturing any topics. The configuration file snippet below shows how:
With this snippet, AMPS enables transaction logging for the instance, but does not capture any messages to the log file. This enables the client name uniqueness checks.