SharePoint and Forms Based Authentication Issue - Office Apps no longer work

Question

We have several sites that use Forms Based authentication (FBA) within SharePoint. Many of them have been running for months without issues. Within the last week or two we have noticed the following behavior for users trying to access a Read Only Microsoft office document (currently only verified with the 2007 versions of Excel and Word).

The behavior we are seeing exhibited:

• The Document starts to open
• Within the Office application an IE Window opens with the FBA login screen. There is also a Hyperlink in the top left saying Skip to main content
• Clicking cancel several times will open the document
• If you identify the site as an IE Trusted site the login screen with the Office app, everything works as before (not an option for the majority of our sites)
• Non offices files, like PDFs, do not exhibit this behavior
• Non IE Browsers that we have tested (FireFox, Chrome) do not exhibit this behavior.

Is anyone else seeing this issue? I assume it was an update sent from Microsoft that has resulted in this issue, since we are seeing it on multiple sites where the code has not been updated.

Thanks

Answer 1

The issue we ran into is there was a policy file applied on our network that caused the UAC prompt to be disabled for Vista/Win 7. When this happens, protected mode gets turned off for the IE browsers, which caused the issues we were seeing.