When trying to connect to an Access '.accdb' file for Inputs or Table data, you may get the following error:
DataReader.Create: Object Reference not set to an instance of the project
This is due to a mismatch in system architecture. If the version of the operating system is 64 bit or the version of Office is 64 bit, this will cause the error as Model Development Studio is a 32 bit application and '.accdb' files are usually 64 bit.
To resolve the issue, do the following:
1. Navigate to https://www.microsoft.com/en-gb/download/confirmation.aspx?id to download the Access Database engine.
2. Once downloaded, run the command line and navigate to the installation location.
3. Run the following command: "AccessDatabaseEngine.exe /passive"
4. This should install the engine. You should now be able to run Model Development Studio and access .accdb files without issue.