Oracle Error Message
RMAN-06757: DB_UNIQUE_NAME “string” does not match target database (“string”)
Reason for the Error
The value specified in the FOR DB_UNIQUE_NAME option did not match the DB_UNIQUE_NAME parameter setting of the target database.
Solution
Use the RMAN STARTUP command, with no parameter file option, to start the target database without a parameter file, then run the RESTORE SPFILE command again.