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How to Solve SQL Database MDF File Not Opening

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How to Solve SQL Database MDF File Not Opening

Learn about database corruption and data files, and how to check, monitor and repair your database files.

· Database Zone ·
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The MDF files are the files that contain database information in SQL Server. They contain the startup information. The extension used is .mdf and it is the primary data file. The databases can contain one primary data file and several secondary data files or none. 

In this article, we will show you how to work with errors related to the MDF file not opening.


You can use any SQL Server version starting with SQL Server 2008 until the last version.

It also applies to any SQL Server edition.

Getting Started

It is a common problem to have a corrupted database. The reasons are multiple. It can be a hard disk failure where the data file is stored. The hard disk failure can be caused by the usage of the disk over the time. If multiple queries are heavily used in the database, it may fail after some years. A blackout can also produce a hardware failure. You can also have problems produced by viruses and worms. In 2003, the SQL Slammer affected to 75,000 servers in ten minutes (and it returned in 2017 to attack some distracted DBAs).

Many viruses attack not only the data files but also the backups. That's why it's strongly recommended to store your backups in a server offline and isolated, if possible. To prevent these problems, you need to use a good firewall, change the default port, and check the shared files and emails. Make sure that the emails are not infecting.

It is usually marked as suspect and the database cannot be used because it is corrupted.

There are several ways to solve this problem. The best way is to use a backup to restore the database. You can combine multiple types of backup to restore your database. It is recommended to check your database backups in case they fail under disaster scenarios. It is also recommended to have a backup in a secure location. There are viruses that attack to data files, log files, and also the backups.

However, if the database is too old you may lose some information from the current days. Another way to restore a database is to use repair commands.

One of the solutions is the DBCC CHECKDB command. This command can show you the integrity database errors, but it also includes options to repair the database.

These commands check the allocation integrity, table integrity, and catalog integrity. It creates a snapshot of the database to do the analysis and contains the following repair options:

  • REPAIR_REBUILD can be used when you want to repair. Use it as your first option to repair the database.
  • REPAIR_ALLOW_DATA_LOSS is used if REPAIR_REBUILD cannot repair the database. This option will lose some data if it cannot be repaired.
  • Finally, you have REPAIR_FAST, which is included for backward compatibility only.

Stellar Phoenix SQL Database Repair is another option that can be used to repair in case that your database is corrupt. This software creates a new MDF file and can be used to recover table data, views, functions, etc.

The first step to repair the database is to download the product. You can download the product using this link.

Once that the product is downloaded, you can install it. Downloading and installing it takes few minutes. To repair, you can use the software. It may require stopping the service and then you will be able to repair the database. It is necessary to specify the path of the corrupted MDF file and if you do not know the location, you can use the tool to locate the file and then you will be able to repair. You can also choose your objects to recover and it can create reports in different formats.


If you cannot open the MDF file and it is in suspected status, your database is corrupt. The first option would be to restore the database. However, your database can be corrupted, or you may not have a current backup. In those cases, it may be necessary to repair using the DBCC commands. In the article, we show different options to repair the database.

There are multiple reasons that can produce this error included hardware problems, virus attacks, and hacker attacks. Viruses and hacker attacks can be closely related. We also gave some recommendations to avoid virus attacks and to secure your database.

Finally, if all the other options fail, you can use third-party tools to repair. We mentioned the Stellar Phoenix SQL Database Repair that can be used to repair a database if it is corrupted. 


For more information about database corruption and data files, and how to check, monitor and repair the files, you can check out the following related links:

sql server ,database ,database error ,mdf files ,sql ,tutorial

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