The block size as stored in the control file header is different from the value of the initialization parameter DB_BLOCK_SIZE. This might be due to an incorrect setting of DB_BLOCK_SIZE, or else might indicate that the control file has either been corrupted or belongs to a different database.
Restore a good copy of the control file. If the control file is known to be clean set the DB_BLOCK_SIZE to match control file headers block size value.
Try the following links for this error:
http://docs.oracle.com/cd/E16655_01/server.121/e26079/e0.htm
https://community.oracle.com/message/1939007
https://community.oracle.com/message/9173778
https://community.oracle.com/message/1459395
https://community.oracle.com/message/4153010
https://community.oracle.com/message/3750803
https://community.oracle.com/message/1962055
https://community.oracle.com/message/3998694
https://community.oracle.com/message/1264867
https://community.oracle.com/message/2395617
https://community.oracle.com/message/3133883
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