I have not tested with other versions of IE, however, as I mentioned, IE using the internal domain works fine. Other browsers e.g. Firefox work externally so I would imagine IE8 does too. I will confirm this shortly. There is no hardware load balancer. It is in fact a single Exchange 2010 server, a very simple setup.

Outlook Web App, published through ForeFront TMG 2010, has unexpectedly broken for external users. IE9 on Win 7 is throwing JavaScript errors similar to the one below. Outlook web access is completely unusable, clicking to expand folders or to view a message in the preview pane does nothing. SCRIPT5022: Exception thrown and not caught uglobal.js, line 1 character 88853 We're running the latest updates on everything including Exchange 2010 SP1. a) What are the general recommendations for IE9 compatibility mode and related settings for Outlook Web App 2010? b) Has anyone encountered similar issues and could suggest how to isolate the issue to ForeFront or OWA?

It it worth mentioning that, unbelievably, OWA works fine externally in FireFox. Hence I am suspecting IE9 / security settings breaking it. The PC being used to test has a fresh install of IE9 and had the default security configuration, I have since tried adding to Trusted Sites etc. and reducing the security level of that zone to no avail.

Hi Edward, Sorry for the misunderstand. Did you make some tests using other version of IE, any issue? Or test owa using IE 9 from internal domain. Do you use Hardware Loadbalance for your CAS servers? Regards! TechNet Subscriber Support in forum If you have any feedback on our support, please contact tngfb@microsoft.com Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.Gavin TechNet Community Support

Hi edward, So, the issue resolved. That seems a issue relevant with IE configuration. Thanks for your sharing. Regards! TechNet Subscriber Supportin forum If you have any feedback on our support, please contact tngfb@microsoft.com Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.Gavin TechNet Community Support

I would not say the issue is resolved, no. I would expect Outlook Web App 2010 to work in IE9 as it is one of the supported browsers.

Hi edward, Per your description, it seems a issue more relevant with client end. I would also make a test using other external client end to make some tests and onfirm whether the issue just happen to special client end. If so, please update the os including the IE. Or, This may sometimes happen if the Internet Explorer browser settings are incorrect , it is suggested that you try to reset the browser settings to default and check if it works. Regards! TechNet Subscriber Support in forum If you have any feedback on our support, please contacttngfb@microsoft.com Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. Gavin TechNet Community Support

One further thing I noticed is that it was only affecting the x86 version of IE9, not the x64 one. After doing a further reset of the IE9 settings from within the 32-bit version, it would appear that the original reset didn't work. The second reset finally got it working. We would really still like an explanation as to how it doensn't work in IE9 after a clean install of Win 7, but for the moment the issue appears to be resolved.

Hi Edward, If you want to confirm what is the casue of the issue, it is better to post the issue on the IE forum, you will get some help about what configuration maybe casued the error. That is, some IE configuration may block some software that needed to be run when using IE to access some web service. Regards! TechNet Subscriber Support in forum If you have any feedback on our support, please contact tngfb@microsoft.com Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.Gavin TechNet Community Support

Hi edward, Per your description, it seems a issue more relevant with client end. I would also make a test using other external client end to make some tests and onfirm whether the issue just happen to special client end. If so, please update the os including the IE. Or, This may sometimes happen if the Internet Explorer browser settings are incorrect , it is suggested that you try to reset the browser settings to default and check if it works. Regards! TechNet Subscriber Support in forum If you have any feedback on our support, please contacttngfb@microsoft.com Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. Gavin TechNet Community Support

As I mentioned it is a fresh install of Windows 7. I used "Reset" on the Advanced tab in the IE9 Internet Options and now it's broken for local access too. Wonderful.