When you try to restore/verifyonly SQL backup you may be found this error some time because the backup may be corrupted.
Solution : Make sure to copy backup file into another device then restore, The issue is on tape/usb/disk
RESTORE VERIFYONLY FROM DISK = 'E:\MSSQL\Backup\MYDBTEST.BAK'
Msg 3242, Level 16, State 2, Line 2
The file on device '\\websql2\SQLBackup\MYDBTEST_2011-06-21-2040.FUL' is not a valid Microsoft Tape Format backup set.
Msg 3013, Level 16, State 1, Line 2
VERIFY DATABASE is terminating abnormally.
RESTORE DATABASE MYDBTEST
FROM DISK = 'E:\MSSQL\Backup\MYDBTEST.BAK'
MOVE 'MYDBTEST_Data' TO 'E:\\MSSQL\DATA\MYDBTEST.mdf',
MOVE 'MYDBTEST_Log' TO 'E:\ MSSQL\DATA\MYDBTEST_log.ldf',
STATS = 5
05 percent processed.
85 percent processed.
90 percent processed.
Msg 3183, Level 16, State 2, Line 1
RESTORE detected an error on page (0:0) in database "MYDBTEST" as read from the backup set.
Msg 3013, Level 16, State 1, Line 1
RESTORE DATABASE is terminating abnormally.