How to Repair Corrupt Microsoft Access Database Files (MDB & ACCDB)?

The Microsoft Access database (.mdb/.accdb) files are prone to corruption and inconsistencies. These files can easily get corrupted due to several reasons, such as a virus attack on the system, hardware failure, software issues, unexpected system shutdown, and sudden closing of Access application. Corruption may also happen due to connectivity issues or when the application is abruptly closed while multiple users are actively working on a shared database file.

Because of this, you may face difficulty in accessing Access database files (.accdb/.mdb) or the objects and fail to execute database queries. You may also encounter an error message like “Unrecognized database format ACCDB/MDB” while trying to open a corrupted database file.

Here are some other error messages related to database corruption:

• The Microsoft Access database is in an inconsistent state.
• Unable to open the access .accdb file.
• MS Access Error 3049: Cannot Open Database
• Microsoft Access isn’t opening .mdb files.
• Microsoft Office Access has detected corruption in this file.
• The database is unexpected.
• Access database error 3112: Record(s) cannot be read; no read permission on ‘xxxx’.
• The database ‘xxxx.mdb’ needs to be repaired or is not a database file.

If you face these corruption errors or cannot open your .mdb or .accdb file, you can resolve the issue by following the DIY Access database repair methods mentioned below. Before proceeding, let’s first understand the Access file formats.

What are MDB & ACCDB Files?

MDB and ACCDB are the two database file types used by different MS Access versions. Let’s read more about them in detail.

MDB: Short for Microsoft Database, MDB file (file extension – .mdb) is a database file type used by the legacy versions of MS Access – 2003 and earlier (till Access 1.0). It stores typical database objects, like queries, tables, forms, and reports.

ACCDB: All latest versions of MS Access – 2007, 2010, 2013, 2016, 2019, 2021, 2024, and Microsoft Access part of Microsoft 365 use ACCDB (.accdb) as the default file type for creating databases. This file format offers advanced features with improved and optimized functionality. With an improved database security model, it supports the security validation of DB files, with the major advantage being that both MS Outlook and SharePoint trust this validation.

Why does an Access Database get Corrupted?

Corruption in Access database can occur due to various operational and system reasons. Some common causes are:

• Frequently editing data in Memo fields (Long text fields)
• Interruptions like network issues when making changes to data
• Jet database engine version conflicts or mismatched service packs
• Virus and malware attacks on the system where you’ve saved the Access database file
• Dissimilar JET Engine service packs
• Improper exit of the MS Access application
• Write operation conflicts due to software incompatibility, hardware failure, or poor network connectivity
• Bad sectors on the storage drive
• Large size of the database file (>2GB)
• Power cut or abrupt system shutdown
• Hardware failure or software bugs
• Conflicting plug-ins

How to Repair Microsoft Access Database?

When your Access database throws error messages or fails to open, you can use various built-in tools, manual recovery methods, or professional Access database repair software to fix it. Depending on the severity of the file damage, use the following methods to repair and restore your corrupt Access database.

Tip – Check this article on MDB file repair for information about common error messages related to MDB File Corruption.

Method 1: Use Compact and Repair Tool to Repair Access Database Manually

You can use Compact and Repair – a Microsoft Access built-in utility for repairing a corrupt .MDB/.ACCDB file. It can also help fix inconsistencies or remove unused spaces in the database file. You can use the Compact and Repair tool in different ways, depending on whether your database is accessible or not.

Case 1. Use Access built-in Tool when Database is Opening

If your database still opens but throws corruption errors, like “unrecognized database format” while running forms or queries—you can run the Compact and Repair tool. To do so, follow these steps:

• Open the problematic Access database file.
• In your Access database, click ‘File.’
• From the window that appears, click the ‘Compact & Repair Database’ option on the ‘Info’ page.

Note: You can also do this from the menu bar. Select Database Tools and click on Compact and Repair Database.

Case 2. Compact and Repair Access Database when it’s not Opening

If you can’t open your ACCDB/MDB file, try repairing the file by using these steps:

Notes:

• These steps apply to Access 2013, 2016, and 2019.
• Take a backup of the database file before proceeding.

• Open your MS Access program.
• On the ‘Templates’ screen, double-click ‘Blank desktop database.’
• In your Access program, click the ‘File’ menu. Next, click ‘Close’ to exit the database.
• Click Database Tools > Compact & Repair Database.

• In the ‘Database to Compact From’ window, locate the corrupt Access database file and select it. Click on Compact.

• The ‘Compact Database Into’ window will appear. Specify a new name for the repaired database file and click ‘Save.’

The repaired file will be saved at the original DB file’s path.

Note: You can even use the command line switch to run the Compact and Repair tool without opening the database.

When this Access Native Tool fails to Resolve Access Database Corruption?

While the built-in utility – Compact and Repair can repair and resolve minor corruption issues in your ACCDB/MDB files, it may not help in severe corruption. When you try to use the tool to repair a severely corrupted database file, it may truncate the data. Also, it may not provide the desired results when repairing large-sized files. It may fail to run if you have not provided the exclusive access to the database that you’re trying to repair.

Method 2: Restore the Database from Backup

If you’ve a backup of your Access database, try using it to restore the database file. The detailed steps are listed below:

• Open File Explorer, select and copy the backup file.
• Paste the copied file at the same location where the corrupt database file is saved.
• When prompted, replace the existing DB file with the backup copy.

For detailed information, read this: How to Backup and Restore Access Database.

Method 3: Delete Microsoft Access Lock Information (.ldb/.laccdb) Files

This is a workaround to restore data from Access database files and is best suited for multi-user environments. Microsoft Access creates temporary lock files (.LDB file for .mdb files and .laccdb for .accdb files) when you open or access a database for shared use. The lock file has the same name as that of the primary file but with the .ldb /.laccdb extension. This helps in keeping track of all active users accessing the database.

When the last user closes the file, this lock file is deleted automatically. But, it might not get deleted if the user doesn’t have delete permissions to the Access database (.mdb) file for that network or the database is corrupt. You can delete the .ldb file or .laccdb file to remove the lock on the .mdb file if you want to recover the data from that file.

Method 4: Use Jet Compact Utility (Deprecated Tool to Repair MDB Files)

The Microsoft Jet Compact utility (JETCOMP.exe) is a deprecated tool that was used to repair corrupt MDB files. It is incompatible with modern database files (.ACCDB). New Access versions use the Access Connectivity Engine (ACE) instead. To repair a corrupt .ACCDB file, you must run the /compact switch via the Microsoft Access (MSACCESS.EXE) command line.

Method 5: Remove all Compiled VBA Codes from the Database

Decompiling VBA codes reverts compiled codes to the source code. It helps to recover corrupt database. This can be done by using this command line switch:

C:\Program Files\Microsoft Office\Office\MsAccess.exe /decompile C:\DatabasePath\FileName.mdb

Note: You may need to change the path shown above for MsAccess.exe if you installed it in a different location.

Method 6: Import Corrupt Database Objects into a New Database

Try importing affected database objects into a new Access database file. It helps recreate the structure of the corrupt file, with its objects. You can copy/import your data into a new blank database by following these steps:

• Open MS Access and create a new database file. To do so, click File > New > Blank Database.
• Next, click the ‘External Data’ tab and select ‘Access’ on the ‘Import & Link’ menu.

• The ‘Get External Data – Access Database’ dialog box is displayed. Click ‘Browse’ and locate the database file that needs to be imported.
• Select Import tables, queries, etc., option under ‘Specify how and where you want to store the data in the current database.’ Click OK.

• Select all database objects you want to import from the next window and then press the OK button.

• The wizard will begin the process of importing the selected objects from the corrupted MDB file into the newly created database file.
• Once it has successfully imported the selected database objects, click Close.

Note: This procedure might also help you repair the Access database file that might have turned corrupt due to damaged system tables.

An Alternate Solution – Use Professional Access Repair Tool

Stellar Repair for Access is a powerful DIY software you can use to repair and recover .MDB/.ACCDB file in a few simple steps. After repair, this Access database repair tool previews all the recoverable database objects, like tables, deleted records, queries, forms, reports, etc. This is useful for the users to verify the data accuracy before saving it.

Follow these steps to perform Access database repair using the software:

• Download, install, and run Stellar Repair for Access software.

• The Select Database window will appear.

• Browse for the corrupt Access database file.

• Click ‘Repair’ to start the repair process.

• After completion of the repair process, various database object categories will be displayed in the left pane.
• Click on ‘+‘ to expand each category. Individual objects under that category will appear.
• Select any object to see its preview.

• To save, click ‘Save Database’ in the ‘Home’ tab.
• The Save At window will appear.
• The Default Location option is selected automatically. This is the location of the source database file. You can choose this or select the New Location option if you want to save the repaired database file at a new path on your local storage drive.
• After selecting an option, click OK to save the repaired database file.

The file will be saved at the desired location.

How to Convert Access Database File Format from MDB to ACCDB?

As per Microsoft’s documentation, you can open MDB files using any new version of MS Access (2007 or later). However, some functionalities of newer Access versions are not supported in the MDB file. So, if you want to use new features, you’ll need to convert MDB to ACCDB first. Here is how you can do this by using Access 2007 or a newer version:

• Launch MS Access.
• Choose the Blank desktop database option.

• Give the new database file a name and click on Create.

• Once the new database file opens, click on File > Close.

• Again, click on File from the ribbon. Select Open from the left pane.
• Select your MDB database file to open it.

• Now, click on File > Save As.
• Choose “Access Database (Default database format)” file type under Save Database As and click Save As.

• Select the location where you want to save the database file and click Save.

• It will show the “Database upgraded” dialog box. Click on OK.

To verify the file format change,

• Go to the location where you have saved the converted database file.
• Select it and right-click on it.
• Click on Properties.

• Check the Type of file field. It should be .accdb.
• Click OK to close the window.

Wrapping Up

An Access database can become corrupt due to numerous reasons, such as database file size (greater than 2GB), hardware issues like bad sectors, or more. We have discussed the tested and effective manual database repair methods above, including the native Compact and Repair utility, to repair the corrupt database. But the MS Access built-in utility may not repair a severely corrupted Access database. In that case, you can use Stellar Repair for Access as a more powerful tool to repair the database. It can effortlessly repair severely corrupted .MDB/.ACCDB files. It can also recover and restore all the database objects from the corrupted file to a new one, with complete integrity.

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