I have an issue with an internally-deployed intranet site (so no links, sorry), and Internet Explorer 9.
The users on site all have either Internet Explorer 8 on Windows XP or Internet Explorer 9 on Windows 7. Users with IE8 are able to use the site as expected, as am I using Chrome.
Users who have IE9 though are able to view pages, but if they try and submit a form, IE loads a blank page, where the source code contains only html, head and body tags. They then find that they can't view any page on the intranet, and the IE back button doesn't work. If I use tcpdump on the intranet server, I can see that when the user clicks submit, no data is sent over the wire from the client, so I can only assume that the blank page (and its source code) is generated by IE.
I have ensured that IE detects the site as being in the "Intranet Zone", and that that zone has the default security setting of Medium-Low. I have tried with Compatibility Mode on (the default for intranet sites) and with it off.
To make matters worse, the behaviour is inconsistent - the form is successfully submitted about 5% of the time, and the rest of the time we have the above result.
I feel like I'm missing something fundamental - what am I missing?