Fixing the Unregistered Microsoft.ACE.OLEDB.12.0 Provider: A Comprehensive Guide

The Microsoft.ACE.OLEDB.12.0 Provider is an important component for database connectivity in various applications, including Microsoft Office applications, and web applications. However, there are instances where you may encounter an error stating that the Microsoft.ACE.OLEDB.12.0 Provider is unregistered on your local machine. This guide provides a comprehensive solution to fix this issue.


Before we start resolving the problem, ensure that you have the following software installed on your system:

  1. Microsoft Access Database Engine 2010 Redistributable
  2. Microsoft Access Database Engine 2016 Redistributable

You can download and install them from the following links:

Step-by-Step Solution

Step 1: Verify the Microsoft.ACE.OLEDB.12.0 Provider Registration

To verify whether the Microsoft.ACE.OLEDB.12.0 Provider is registered on your local machine, follow the steps below:

  1. Press Win + R to open the Run dialog.
  2. Type regedit and press Enter to open the Registry Editor.
  3. Navigate to the following path:

If you find the Microsoft.ACE.OLEDB.12.0 key under Classes, it means the provider is registered. Otherwise, proceed to the next step.

Step 2: Install the Microsoft Access Database Engine

If the Microsoft.ACE.OLEDB.12.0 Provider is not registered, you need to install the Microsoft Access Database Engine. Download and install the appropriate version (32-bit or 64-bit) from the links provided in the Prerequisites section.

Step 3: Check the Target Platform of Your Application

Ensure that your application's target platform matches the installed version of the Microsoft Access Database Engine. Follow these steps to check and modify the target platform:

  1. Open your project in Visual Studio.
  2. Right-click on the project in the Solution Explorer and select Properties.
  3. In the Properties window, navigate to the Build tab.
  4. Under the Platform Target dropdown, select the appropriate platform (x86 for 32-bit or x64 for 64-bit) to match the installed version of the Microsoft Access Database Engine.
  5. Save and rebuild your project.

Step 4: Test the Microsoft.ACE.OLEDB.12.0 Provider

After successfully installing the Microsoft Access Database Engine and setting the target platform, test the Microsoft.ACE.OLEDB.12.0 Provider in your application. If everything is configured correctly, you should no longer encounter the "unregistered" error.

Frequently Asked Questions

1. What is the Microsoft.ACE.OLEDB.12.0 Provider?

The Microsoft.ACE.OLEDB.12.0 Provider is a database engine that allows applications to access and manipulate various types of data stored in Microsoft Office files, such as Access databases and Excel spreadsheets.

2. What causes the "unregistered Microsoft.ACE.OLEDB.12.0 Provider" error?

This error occurs when the Microsoft.ACE.OLEDB.12.0 Provider is not installed or registered on the local machine or when there is a mismatch between the application's target platform and the installed version of the Microsoft Access Database Engine.

3. How do I determine whether I need the 32-bit or 64-bit version of the Microsoft Access Database Engine?

You should install the version that matches your application's target platform. If your application targets the x86 (32-bit) platform, install the 32-bit version. If your application targets the x64 (64-bit) platform, install the 64-bit version.

4. Can I install both the 32-bit and 64-bit versions of the Microsoft Access Database Engine on the same machine?

Yes, you can install both versions on the same machine. However, you may encounter issues if you try to install them side-by-side using the default installer. To install both versions, refer to this guide on installing the 32-bit and 64-bit versions of the Microsoft Access Database Engine side-by-side.

5. Are there any alternative providers that I can use instead of the Microsoft.ACE.OLEDB.12.0 Provider?

Yes, you can use alternative providers such as the Microsoft.Jet.OLEDB.4.0 Provider for Access databases or the ODBC drivers for Excel spreadsheets. However, these providers may have limited functionality and compatibility compared to the Microsoft.ACE.OLEDB.12.0 Provider.

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