SQL Server Database Restore Problem

am having problem restoring SQL database from the back up file.

I had to format my PC to solve the main software problem which was using SQL server 2012.

I took backup without .bak extension but later i have added .bak extension to the file.

when i proceeded for restore after new windows and SQL server setup, it is showing below errpr:

"Backup mediaset is not complete. Files: D:\SQL Backup\25.09.2016\TrendData.bak. Family count:2. Missing family sequence number:1"

How can I resolve this issue?

Does RESTORE HEADERONLY give some indication of the backup contents (e.g. if two backup files were made as part of a "set")? I can't remember, sorry.

RESTORE HEADERONLY FROM DISK = 'D:\SQL Backup\25.09.2016\TrendData.bak'

The other possibility is to check the tables in MSDB (on the server the backup was made on) for the Backup History details.

the backup was created in one step. there is no part.
i am also confused if backup file is healthy or it is un-usable. there was no error during backup.

Make sure your backup is valid or not. See here:

https://www.mssqltips.com/sqlservertutorial/113/checking-to-make-sure-a-sql-server-backup-is-useable/

If you found any issue in backup file, then you take the help of third party SQL backup file recovery tool to fix the backup file issues.

Easy to repair corrupt or damaged SQL server database, I would like to suggest an effective tool Kernel for SQL Database Recovery Tool. This tool easy to recovers corrupt or damaged SQL database. Visit here - http://www.en.sqlrepair.org

"Oh no it isn't" !!!

SOMETIMES it is, but that is a rare bird.

Have you visited this? - http://wordpress.semnaitik.com/2014/02/22/repair-sql-database/

Here in this blog post, you'll get an easy manual trick to repair SQL database file. I hope it would be helpful here.

Thanks and best regards.