Asp.net web api exception only after deploying at IIS : A route named 'HelpPage_Default' is already in the route collection

I just ran into the same issue. I think the error was caused because I had pushed another solution to my site previously and there were leftover files that were somehow getting in the way.

To fix this I checked the box that says "Remove additional files at destination" while publishing through Visual Studio to my Azure site. I would assume you could just manually delete any old files that were on the server before publishing as well. After this the site ran fine with no errors.


  1. Right click your solution in Visual Studio -> click Clean Solution
  2. Remove all files under your \Project\bin\ folders
  3. Rebuild your solution in Visual Studio Cheers.

I renamed a Namespace by refactoring it and doing that missed this hardcoded string:

Project > Areas > HelpPage > AppStart:

public static class HelpPageConfig
    {
        [SuppressMessage("Microsoft.Globalization", "CA1303:Do not pass literals as localized parameters",
            MessageId = "<CORRECT NAMESPACE>.Areas.HelpPage.TextSample.#ctor(System.String)",