Are you connected to a library server? If so, on what platform?
Yes, Client and library server are both running macOS 15.2. Client (on which the hang occurs) currently running MC 33.0.44. Library server running MC 33.0.30.
Another client, loading the same library, is running macOS 12.7.8 and MC 33.0.30. That client does *not* exhibit the hang.