Client closes but the process is still running

I have reports from two end users that the GroupWise client running on Windows 10, closes and will not re-open because the "process" is still running.  To solve it the process must be closed and GroupWise re-launched.  The server is running 18.1.1, the clients started at 14.2.2 and to try and solve it were updated to 18.1.1.

Is anyone else seeing this behavior?  If so is there a fix?