Where/how can I download (and install) the Microsoft.Jet.OLEDB.4.0 for Windows 8, 64 bit?

Question

I've got a 32 bit .net 2.0 app that uses the Jet OLEDB 4.0.

It runs fin on Windows 8 32 bit, but not on the 64 bit. on 64 bit I'm getting an error:

'Microsoft.Jet.OLEDB.4.0' provider is not registered on the local machine. at System.Data.OleDb.OleDbServicesWrapper.GetDataSource(OleDbConnectionString constr, DataSourceWrapper& datasrcWrapper)

I am aware that you can't use that database (driver) with a 64 bit EXE. However I've not read anything about it not working with the 32 bit exe.

What I tried:

1. Installed the MS Access Database Engine 2010 32 bit (and restarted)
2. Verified that msjet40.dll is in the "C:\Windows\SysWOW64\msjet40.dll" directory and registered it with RegSvr32.

So I think (hope) that if I can install the database support it'll just work.

Problem is, I can't find any place to download it.

Answer 1

On modern Windows this driver isn't available by default anymore, but you can download as Microsoft Access Database Engine 2010 Redistributable on the MS site. If your app is 32 bits be sure to download and install the 32 bits variant because to my knowledge the 32 and 64 bit variant cannot coexist.

Depending on how your app locates its db driver, that might be all that's needed. However, if you use an UDL file there's one extra step - you need to edit that file. Unfortunately, on a 64bits machine the wizard used to edit UDL files is 64 bits by default, it won't see the JET driver and just slap whatever driver it finds first in the UDL file. There are 2 ways to solve this issue:

1. start the 32 bits UDL wizard like this: C:\Windows\syswow64\rundll32.exe "C:\Program Files (x86)\Common Files\System\Ole DB\oledb32.dll",OpenDSLFile C:\path\to\your.udl. Note that I could use this technique on a Win7 64 Pro, but it didn't work on a Server 2008R2 (could be my mistake, just mentioning)
2. open the UDL file in Notepad or another text editor, it should more or less have this format:

[oledb] ; Everything after this line is an OLE DB initstring Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\Path\To\The\database.mdb;Persist Security Info=False

That should allow your app to start correctly.

Answer 2

Make sure to target x86 on your project in Visual Studio. This should fix your trouble.