Cannot delete From: addresses in Exchange 2010 OWA's

Question

I'm trying to clear the cache in the from: field of Exchange 2010 OWA. The user had send as permission to an account that does not have anymore, and I can't remove the cache.

I'm attaching a picture of the problem. Pressing Delete, Fn+Delete, Backspace in the OWA only works with the To: field. Not in From: field.

How to delete those three address?

Answer 1

According to Microsoft, the thing to do is to reattach the mailbox and then remove the send as permission to make that go away. If that's not an option, you could remove the permission manually, though that's a fair bit more involved, and there's no telling what fun little issues that might create down the line.