var assemDir = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);

var current = AppDomain.CurrentDomain;

IAddInFactory addinFactory;

try

{

    // assume 64bit is more common now

    var addInAssemName = AssemblyName.GetAssemblyName(Path.Combine(assemDir, @"Redbolts.AddIn.AddIn64Factory.dll")).FullName;

    addinFactory = (IAddInFactory)current.CreateInstanceAndUnwrap(addInAssemName,

        "Redbolts.AddIn.AddIn64Factory.AddInFactory", 

        false, BindingFlags.Default, null, null , null, null, null);

    Console.WriteLine("Successfully loaded 64bit OS version of RevitAddInUtility");

}

catch (Exception ex)

{

    addinFactory = (IAddInFactory)current.CreateInstanceFromAndUnwrap(Path.Combine(assemDir, @"OS32\Redbolts.AddIn.AddIn32Factory.dll"),

        "Redbolts.AddIn.AddIn32Factory.AddInFactory",

        false, BindingFlags.Default, null, null, null, null, null);

    Console.WriteLine("Successfully loaded 32bit OS version of RevitAddInUtility");

}

if (addinFactory!= null)

{

    Console.WriteLine(addinFactory.RevitInstalledApplications.Count());

    foreach (string revitInstalledApplication in addinFactory.RevitInstalledApplications)

    {

        Console.WriteLine(revitInstalledApplication);

    }

}

Console.ReadLine();