Oracle Message ORA-01622 - thread number must be specified - default not specific

ERRORthread number must be specified - default not specific
CAUSEThe thread was not specified when adding a log, and the currently mounted thread was chosen by default at mount time. Since the current thread was not specified explicitly the user cannot know which thread the log will be added to.
ACTIONExplicitly specify the thread number either in the INIT.ORA parameter thread, or in the add command.