
You have a long-running backup in the Microsoft SQL database and you want to terminate it.
Launch the Microsoft SQL Studio and execute the following SQL query and take note on the SPID.
SELECT session_id as SPID, command, a.text AS Query, start_time, percent_complete,
dateadd(second,estimated_completion_time/1000, getdate()) as estimated_completion_time
FROM sys.dm_exec_requests r CROSS APPLY sys.dm_exec_sql_text(r.sql_handle) a
WHERE r.command in ('BACKUP DATABASE','RESTORE DATABASE')

Now, to terminate or to kill the running backup – use the following query,
kill SPID
#Example
kill 114