oracle error - ORA-00209: control file blocksize mismatch, check alert log for more info

ORA-00209:

control file blocksize mismatch, check alert log for more info
Cause: The block size in the control file header does not match the size specified in the DB_BLOCK_SIZE parameter.
Action: Look at the alert log for more information.

oracle error - ORA-00208: number of control file names exceeds limit of string

ORA-00208:

number of control file names exceeds limit of string
Cause: An attempt was made to use more control files than Oracle supports.
Action: Shut down Oracle. Reduce the number of control files specified in the CONTROL_FILES parameter in the initialization parameter file, and restart Oracle. Delete usused files.

oracle error - ORA-00207: control files are not for the same database

ORA-00207:

control files are not for the same database
Cause: The database ID in the control file is not the same as the database ID in the control file used by the first instance to mount this database. Most likely one of the mounts used the wrong control file or there are two databases with the same name.
Action: Check that the control file is for the correct database and is not an old version.