SharePoint 2010 ‘allowInsecureTransport’ error

I’ve been working with SharePoint 2010 and Word Automation Services quite a bit these days. I recently ran into an error that I just could not figure out. There’s very little out there on teh interwebs, and the only solution that I found sounded perfect. At first.

When attempting to convert a file from .docx to .pdf via Word Automation Services we were receiving:

Unrecognized attribute ‘allowInsecureTransport’. Note that attribute names are case-sensitive. (D:\Program Files\Microsoft Office Servers\14.0\WebServices\WordServer\Proxy.config line 77)

This was a brand new SharePoint install and everything appeared to be configured correctly. The ONLY solution that I could find was to apply a .NET hotfix (KB976462). It made sense. It sounded perfect! However… the .dlls that the hotfix wanted to apply were at an older version than what was already on the SharePoint server. At this point, we opened a case with Microsoft…

Microsoft found that more than just the Word Automation Services were generating this error – the Security Token Service and Search were also generating this error. It took about 2 weeks, but we were able to find the culprit.

It was in fact a .NET patch – but it was not KB976462. In our case, one of the SharePoint 2010 prerequisites had failed during the install and no one had noticed. This particular patch did not actually prevent the installation of SharePoint, so it continued to go unnoticed until we started experiencing problems.

I don’t recall the exact patch that was missed – if I find it, I’ll update this post. We could have just re-run the Prerequisites Installer to have it applied, but in our case Microsoft just sent us the patch.

If you run into this scenario, take a look through your prerequisites log – if you still have it.