How to solve ORA-011033: ORACLE initialization or shutdown in progress I have followed link  to solve the problem.

When it is giving ORA-00600: internal error code, arguments: [kcratr1_lostwrt] then I am using: 

SQL&gt; startup mount


the above line should return ORACLE Instance started
but it is showing "cannot start already-running Oracle - shut it down first".
ORA-00600 is Oracle's generic message for un-handled internal exceptions i.e. bugs.  Usually they require us to raise an SR with Oracle Support.    This can be a problem for sites who are using Oracle without a support contract.  In that situation we are thrown on the resources of the internet.  

The problem you are experiencing is due to a corrupted block.  The top result in Google offers a simple workaround: find out more. 

SQL&gt; shutdown immediate;
SQL&gt; startup mount;
SQL&gt; recover database;
SQL&gt; alter database open;


(Of course, this is only a solution if you are running in archivelog mode, and so can recover the lost block).