How to verify the Backup file in SQL Server.

RESTORE VERIFYONLY FROM DISK = 'B:\Backup\ALEXPPP_12102017.bak'

GO

--if you got below Result Set that means backup file is restorable.

--Attempting to restore this backup may encounter storage space problems. Subsequent messages will provide details.

--The path specified by "D:\SQLData\ALEXP_System.mdf" is not in a valid directory.

--Directory lookup for the file "D:\SQLData\ALEXP_Data.ndf" failed with the operating system error 2(The system cannot find the file specified.).

--Directory lookup for the file "D:\SQLData\ALEXP_Data_1.ndf" failed with the operating system error 2(The system cannot find the file specified.).

--Directory lookup for the file "D:\SQLData\ALEXP_Data_2.ndf" failed with the operating system error 2(The system cannot find the file specified.).

--Directory lookup for the file "D:\SQLData\ALEXP_Data_3.ndf" failed with the operating system error 2(The system cannot find the file specified.).

--Directory lookup for the file "L:\SQLLogs\ALEXP_Log.ldf" failed with the operating system error 2(The system cannot find the file specified.).

--The backup set on file 1 is valid.