The 'Microsoft.ACE.OLEDB.12.0' provider is not registered on the local machine

When ASP.NET Web API try to connect with Microsoft Access it raise error 'The 'Microsoft.ACE.OLEDB.12.0' provider is not registered on the local machine'

If you have built your project under x86 platform, then in order to resolve you issue you should install the following packages on your machine:

In order to use the 'Microsoft.ACE.OLEDB.12.0' provider you must install the Microsoft Access Database Engine 2010 Redistributable first, this installation is available at: http://www.microsoft.com/download/en/details.aspx?id=13255 .

After the installation has complete, try running you application, if this solves the issue great, if not, continue to step 2.

If you are trying to run an application built under x64 or AnyCPU platform, I would recommend first validating that it runs as expected under the x86 platform. In the event that it does not run under that x86 platform, perform the steps in the first part and validate that it runs as expected.

3-Change in its App pool 'advanced settings' to allow to run 32-bit programs... that did it for me.

Ref:Stack over flow ref