How to Repair MDF File?

   Author : Amelia Williams | Updated on October 22, 2018

An SQL database typically stores thousands of records, and its size keeps expanding each day. Organizations using SQL databases regularly perform a number of updates, alterations, and modify operations on the database often resulting in database inconsistencies. And inconsistencies within an SQL database could lead to eventual database corruption. These disorder a database corruption can bring on an organization can't even be imagined. Thus, being aware of the causes, preventive measures and solutions for corruption in SQL database files can be one perfect way of handling an MS SQL Server.

To be able to repair a corrupt MS SQL Server Database file, we need to first understand its primary database file, the MDF file, whose damage or corruption, ultimately leads to a failed SQL server.

What is an MDF file?

An MDF file is the primary database file, which contains the database schema and data. In addition to this file, the SQL database also uses an LDF file, which contains database logs and a secondary database file with .NDF extension.

Considering that the MDF file is the most important file of the SQL database, in the event of any damage to it, the whole database could become corrupt. And more often than not, the real cause behind SQL database corruption is MDF file corruption. To find a solution for a corrupt MDF file, let us first know the reasons behind the issue.

Reasons behind MDF file corruption

There could be several causes that trigger an MDF file corruption:

  • Platform issue: Third-party drivers or firmware bug in the layer below the SQL server
  • Hardware fault: Problems in Disk, Controller, CPU, or Memory Modules
  • Disk Subsystem: SQL Server depends on Disk Subsystem for storing and retrieving data. Thus any issue in disk controllers, communication channels or in the disk Subsystem can cause database corruption
  • Bugs within Microsoft products
  • Improper system shutdown owing to power outage or hard restart
  • Virus infection to one or more volumes on the server
  • Technical faults within external drives or other storage devices connected to the server

So, what is the best way to repair MDF files and save all the precious data stored within them?

Free ways to repair MDF File

A corrupted MDF file can be repaired in the following free ways:

  • Executing the DBCC CHECKDB command (built-in)
  • Restoring MDF file from a recent backup
  • Note: Though both methods can be used in most cases, however, they are not without their limitations:

  • The "DBCC CHECKDB" command is often unable to fix major MDF file corruption
  • Corruption doesn't come with a warning; thus, when your SQL database gets impacted, you may not necessarily have a recent backup at hand

Hence, in situations where usual methods fail to revive a damaged MDF file, using a trustworthy MDF repair software is the best solution for salvaging data within the database.

MDF File Repair using Stellar SQL Database Repair Software

Stellar Repair for MS SQL is a proficient tool that fixes even the severest of corruptions within MDF as well as NDF files and recovers inaccessible objects from them. The product carries out an advanced non-destructive repair to preserve database integrity during the process. It is equipped with an impressive feature set to help you repair MDF file smoothly and with precision.

Here are the remarkable features of this application at a glance:

  • Repairs corrupt MDF / NDF files & recovers tables, triggers, indexes, keys, rules &  defaults
  • Allows searching and recovering specific database objects
  • Facilitates saving repaired file in MS SQL, HTML, XLS & CSV formats
  • Enables deleted record recovery while performing repair process
  • Supports ROW and PAGE compressed data recovery
  • Supports SCSU (Standard Compression Scheme for Unicode) for SQL Server 2008 R2
  • Recovers all data in original format
  • Reconnects to SQL server automatically if there is a disruption during the repair process

In addition to the above features, this Microsoft SQL server database recovery tool has an interactive and easy to follow user interface and a number of customizable options that make working with it extremely simple.

Steps to repair the MDF File

Using Stellar SQL repair software, follow the steps below to mend the MDF file with ease:

  • Download, install and launch the product
  • A pop-up will appear on the main screen that says, "Stop MS SQL Server and copy database to different location. Restart the server and repair the copy of database." Follow these instructions and click 'OK' on the pop-up.

Select the corrupt database file for repair.

  1. If you know the file's exact location on the system, browse and select it. 
  2. If you're unaware of its location, click on 'Search in Folder' button to select a target folder and click on 'Find' button to look for the file.
  3. Once the corrupted MDF file has been selected, click on 'Repair' button to initiate the repair process.
  4. As objects are discovered, they'll be populated in a tree-view list on the left panel of the screen.
  5. Click on any object to preview it in the right panel of the screen
  6. You'll be prompted to select the desired output format to save the repaired database (MSSQL, CSV, HTML, or XLS)
  7. Also, you'll be allowed to pick the desired location to save the resultant file. Once you've provided both options, click on 'OK.'
  8. Finally, you will be asked if you wish to save the repaired file in the existing database or a new one. Select the appropriate choice and click on 'OK' to complete the process.

Product Specifications

This Do-It-Yourself (DIY) software is easy to download and takes only a couple of seconds to install. Moreover, it has very low system requirements and a wide compatibility index.

Version: 8.0

Operating System: Windows Server 2012, 2008 & 2003 and Windows 10, 8.1, 8, 7, Vista & XP

Memory: 1 GB RAM minimum (2 GB recommended)

Hard Disk: At least 50 MB free disk space

MS SQL Server: 2016, 2014, 2012, 2008 R2, 2008, 2008*64, 2008 Express, 2005, 2005*64, Express, 2000, 2000*64, 7.0, and mixed formats

Frequently Asked Questions

Q. The product usage suggests copying the database to a different location and running the repair process on the copy. Can you explain why?

A. This is simply a precautionary measure. Running repair process on a database copy helps mitigate the risks of any accidental damage to the file. The software by itself is equipped to prevent any modifications to your database. However, if something goes wrong (power spike, system glitch), you may run the risk of damaging the database structure or the contents of your database file.

Q. What happens if the software is not able to repair my corrupted MDF file?

A. Such a situation is very rare and can only happen in case the file is severely corrupt and is beyond recovery by any application. In such a case, you need to send it to us so that our professionals can analyze and repair the file. You can reach us via email at support@stellarinfo.com

Q. Some data is missing from a few tables in my SQL database. What could be wrong and how can I fix this problem?

A. It seems that your SQL database is damaged. You need to take quick action before the database becomes totally corrupt. Stop the database immediately and look for a reliable database repair software like Stellar Repair for MS SQL. Use the software to fix issues within the database's MDF file and save all your critical data.

Q. My SQL database is badly damaged. Whenever I try to run DBCC CHECKDB commands, I get error codes 8942 & 3414. I haven't been able to rectify these two error codes with any other product. Can Stellar SQL repair software help me out?

A. Indeed it can! This mdf file repair software is capable of fixing a number of SQL Server database corruption errors such as 5171, 8942, 3414, not a primary database file, header file corruption, database in suspect mode, clustered or non-clustered index corruption, consistency error, schema corruption and much more.

Q. I have accidentally deleted a few important records along with other records I didn't need. Please help me get them back!

A. Stellar Repair for MS SQL performs deleted records recovery while performing MDF file repair function. With this tool you can restore all your deleted records without any modifications in the original hierarchy and save them in a newly created table.

Q. I have multiple NDF files associated with the MDF file. Can MDF file repair software repairs the data from all associated NDF files?

A. Yes, Stellar Repair for MS SQL can repair MDF file and all NDF files associated with it. Keep all the associated NDF files at the location of corrupt MDF file.

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