HKEY_CLASSES_ROOT\CLSID\3BE786A0-0366-4F5C-8FB8-95E3565CAF27 If present, the driver is ready. | Tool / Language | Connection string example | |----------------|---------------------------| | Python (pandas) | engine='access' or conn_str = r"DRIVER=Microsoft Access Driver (*.mdb, *.accdb);DBQ=C:\data\file.accdb" | | PowerShell | $conn = New-Object System.Data.OleDb.OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\data\file.xlsx;Extended Properties='Excel 12.0 Xml;HDR=YES'") | | SQL Server (Linked Server) | Provider = 'Microsoft.ACE.OLEDB.12.0'; Data Source = 'C:\data\file.accdb' | | C# / .NET | @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\data\file.xlsx;Extended Properties=""Excel 12.0 Xml;HDR=YES""" | Troubleshooting tips ❌ “The ‘Microsoft.ACE.OLEDB.12.0’ provider is not registered” → You installed the 64-bit version, but your app is 32-bit (or vice versa). Reinstall the 32-bit driver using /quiet if needed.

If you’ve ever tried to work with .xlsx , .xls , or .accdb files outside of Excel or Access—especially in PowerShell , Python (pandas) , C# , or SQL Server Integration Services (SSIS) —you’ve likely encountered this error: The ‘Microsoft.ACE.OLEDB.12.0’ provider is not registered on the local machine. The solution? The Microsoft Access Database Engine 2010 Redistributable (32-bit).

– if you already have Microsoft Office 64-bit installed , the installer will block with a warning: You cannot install the 32-bit version of the Access Database Engine because you have 64-bit Office products installed. The workaround (forced quiet install) Open Command Prompt as Administrator and run:

Look for the file named: (that’s the 32-bit version) The 64-bit version is named AccessDatabaseEngine_x64.exe . Do not grab that unless you are 100% sure your toolchain supports 64-bit ACE. Step 2: Install normally (with one big exception) Run AccessDatabaseEngine.exe . The default install is straightforward.

For 99% of mixed-environment scenarios (32-bit scripts + 64-bit Office), the 32-bit ACE 2010 redistributable remains the correct, battle-tested answer. Have you run into the “bitness mismatch” error? Let me know in the comments — I’ve been fighting that dialog since 2012.

AccessDatabaseEngine.exe /quiet Or, to see progress but bypass the version check:

Go to the official Microsoft Download Center: