I have been having issues with setups on IIS NOT returning any informative errors what-so-ever. It seems that everything that happens just triggers a 500 Server Error, which is about as helpful as a swift kick in the groin. I have 3 example images from the exact same error on 3 different environments.

Production View: enter image description here

Production View (Detailed errors on): enter image description here

Local View (Running through EasyPHP): enter image description here

Is there not some way to process the errors through IIS in a more legible manner? The logs don't show the issues either.


As I started digging into it and actually looking (oops), the errors are CI/EE messages. How would I go about enabling those instead of standard IIS 500 errors?

  • config.php => $config['debug'] = "2"; ?
    – Max Lazar
    Oct 29, 2013 at 18:03
  • 1
    I'd venture to say that the messages on your IIS servers are unrelated to the error you're seeing locally. 500 errors happen more at the server level and usually have to do with server config, .htaccess, or something really bad happening in PHP. The database error shown locally has not triggered a 500 error, since it's displaying the CodeIgniter error. Oct 29, 2013 at 18:15
  • Jeremy, I thought the same, but this is the case on others as well. If the CI codes the error as a 500 error numeric value, as in this case, the IIS error processing does not allow the message to go through. The server stops it dead in its tracks and throws the IIS system 500 message.
    – W3bGuy
    Oct 29, 2013 at 18:53

1 Answer 1


For anyone who runs into this, I resolved it by modifying the web.config file to allow errors to "PassThrough".

I changed the following:

<httpErrors errorMode="Custom" existingResponse="Replace">


<httpErrors errorMode="Custom" existingResponse="PassThrough">

This resolved the issue I was facing. However, I wil only turn this on when I see an error to get a better feel of what it is. rather than exposing the full error message to the public.

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