Problem Statement

The transaction log for database is full due to LOG_BACKUP.

Solution

You can truncate the transaction log file size using below SQL command sequence in SQL 2012 on your Windows Server
  1. Login in database server.
  2. Select the database
  3. Click on new query
  4. Execute following SQL commands (replace the 'databasename' with your database name at all places in below commands.

    ALTER DATABASE [databasename] SET RECOVERY SIMPLE
    GO
    DBCC SHRINKFILE ([databasename_Log], 5)
    GO
    ALTER DATABASE [databasename] SET RECOVERY FULL
    GO