ERROR - "the 'microsoft.ace.oledb.12.0' provider is not registered on the local machine" - RESOLUTION

Scenario:

ERROR - "the 'microsoft.ace.oledb.12.0' provider is not registered on the local machine"

RESOLUTION :

There are lot of scenarios for which we might get "The 'Microsoft.ACE.OLEDB.12.0' provider is not registered on the local machine" error when attempting to connect to either an accdb or an xlsx file. 

I have spent a couple of hours searching Google for a resolution of this issue but somehow I was not getting the correct solution. Ultimately, the below solution worked best for me 100%.

Step 1. download and install this: http://www.microsoft.com/download/en/confirmation.aspx?id=23734/ 

Step 2. in VS, add references (say Microsoft.Office.Interop.Excel)  and write necessary business logic. 

Hope this helps.. Cheers... :)

Check-box 'Prefer 32-bit' disabled in Visual Studio 2012. Why?

Question: 

Check-box 'Prefer 32-bit' disabled in Visual Studio 2012. Why?

Answer: 

In Visual Studio, Switch the project to .NET 4.5 (on the Build tab of the project properties). This would re-enable the check-box "Prefer 32 bit" for AnyCPU.