Database transaction log file has grown very large (4293441)

Over time, the database transaction log file (LDF) has grown very large.  This is due to the fact that the database is set to the Full Recovery model and the transaction log file has not been backed up recently.

By default, in SQL Server 2008 and above, the recovery model for a SQL Server database is set to the full recovery model.  With the full recovery model, regular backups of the transaction log are used to prevent the transaction log file size from growing out of proportion to the database size.  However, if the regular backups of the transaction log are not performed, the transaction log file grows to fill the disk, and you may not be able to perform any data modification operations on the SQL Server database.

The best solution is to create a maintenance plan to regularly backup and shrink the transaction log file.  This will ensure that all transactions that have already been committed to the database are truncated from the transaction log file.  Alternatively, the database recovery model can be changed to simple mode if the point of failure recovery is not necessary to you.  (Generally, the Full Recovery model is preferred for production databases so this option is not recommended). 

The database must also be configured with these settings:

1. Auto close = False
2. Auto shrink = False
3. Restrict Access = Multi-User

After that detach, re-attach it, and perform a shrink of the database

For more information, please review the following Microsoft article on choosing the proper recovery model, and maintaining the transaction log.

Related Articles or Solutions:

MS: Choosing the Recovery Model for a Database

Troubleshoot a Full Transaction Log (SQL Server Error 9002)