Oracle Solution for Error ora-01648

ORA-01648: log string is the current log of disabled instance string (thread string)

What triggered the Error:

An attempt to enable the thread failed after it was half completed. This log was left as the current log even though the thread is still disabled. Since a log switch cannot be done until the thread is enabled, the log can not be cleared or archived.

What should we do to fix it:

Complete the thread enable by issuing the enable command again.