database - Attempt to break deadlock? -

I want to change schema .... First drop, then import with impdp ....

  SQL & gt; Drop user user cascade; .... Do not hang any answer ...  

Check the warning log:

  ORA-200060: Deadlock detected. More information in file / u01 / app / oracle / output from output /procu/procu/trace/procu_ora_2833.trc: /procu_ora_2833.trc 9: DB session process is not connected to the end of the state's XS session *** 2015 - 03-02 08: 53: 25.276  

ORA -0060 signals attempt to break deadlock by

Please help me in this ???