I was trying to change the properties of a look up field and was greeted by this:
After a little searching I came across KB2743941.
Microsoft Dynamics CRM 2011 with Update Rollup 10 is compatible with Internet Explorer 10 in Compatibility Mode.
Dynamics CRM 2011 compatibility with other modes of Internet Explorer 10 will be announced at a later date.So as a workaround you need to turn on compatibility mode for all sites, or just add the domain name(s) for your CRM server(s).
Alt-T will display the tools menu if you don’t see it and then look for Compatibility View settings.
You can either choose to Display all websites in Compatibility view or add dynamics.com (for CRM Online) or your domain name to the list.