We test our applications often using ‘RunAs’ to run Internet Explorer under a different session. I know that SharePoint allows you to ‘Log in as a different user’ but it doesn’t always work that well for us (i.e. you log in repeatedly and it might let you in).

One of my colleagues was trying to edit a document logged into Windows as one user, but running his IE session at a different user. Clicking on the document opened it Word in IE – despite that the Library should try and open documents in their client application. Trying to edit the document he got the message:

‘Edit Document’ requires a Windows SharePoint Services-compatible application and Microsoft Internet Explorer 6.0 or greater.

This is the same message as mentioned in KB833714, but a different cause. When I tried editing the same action but as the user he was logged into Windows as it worked fine.