Sometimes, you may get an error as follows while restoring a database in MSSql

Error: dbbackup failed: Unable to restore database 'test_test'
Not valid backup
The media family on device 'C:
WINDOWSTEMPlocalhosttest_testtest.bak' is incorrectly formed.
SQL Server cannot process this media family.
VERIFY DATABASE is terminating abnormally.

Most probably this error occurs when you are trying to restore an SQL backup generated in SQL 2008 to an SQL 2005 server. So, to get it correctly restored, we need to make the backup 2005 compatible. You can do it as follows.

1) Open SQL Server Management Studio2008. In 'Object Explorer', right click the database that you want to convert.

Select 'Tasks' > 'Generate Scripts'. 

2) Click 'Next'...