EDIT 10/17/2011: The fix for this issue is now available. Please go here to learn how to get it.
We wanted to write a blog post about an issue that some of you have reported to us, and has been discussed at some length in Exchange Forums also.
After you install Internet Explorer 9 on a computer that has Exchange 2010 or Exchange 2007 management tools installed, you might run into a situation where closing the Exchange Management Console (EMC) results in the following error:
You must close all dialog boxes before you can close Exchange Management Console
This might happen even if there are no property pages left opened that you can see. Please note here that not all of our customers who installed IE9 on a computer with Exchange management tools (server or workstation) have run into this problem.
Are there any workarounds?
As it stands right now, we are not aware of a reliable workaround for this problem. Terminating the EMC using the Task Manager (or possibly a command or script) does not have adverse effects on management tools functionality, but is clearly a non-optimal solution.
What are we doing to address this?
The EMC is implemented as a Microsoft Management Console snap-in. We are working closely with both MMC and Internet Explorer teams to find a solution to this problem. Due to the complex nature of several products involved and the interoperability between them, identifying the root cause was not simple; things are still in process and we do not have a firm solution or a date to share with you yet. We do, however, want to say that we are very aware of this issue and several teams are collaborating and working to get this addressed. Once more details are available, we will be sure to share them here.