RESTORE filelistonly FROM DISK = N'E:\MSSQL\My2012Backup'
Ooops. Trying to restore a more current database backup on an older server got me this error.
Msg 3241, Level 16, State 13, Line 2 The media family on device 'E:\MSSQL\My2012backup' is incorrectly formed. SQL Server cannot process this media family. Msg 3013, Level 16, State 1, Line 2 RESTORE FILELIST is terminating abnormally.
Run the restore command on a newer version of SQL fixes the error.