I am pulling my hair out over an issue that I cannot solve. I'm hoping the community can help. Our organization uses MS Outlook 2010 64-bit in conjunction with Exchange 2010. All patches are up to date on the client and server side. Workstations run Windows 7 Pro 64-bit. When a person makes a meeting request and the recipient accepts it, it all works like clockwork. If recipient goes into said meeting request later and wants to respond to all or just the Organizer, the send function fails. For example, I have a meeting request open that I accepted today. If I open the meeting request and click on respond and reply or reply all, it will open a window where you can reply. I will type in my response and click send and nothing happens. The email doesn't send nor does it disappear. Has anyone here experienced this behavior before? This problem is global within our organization from either outside email requests as well as internal. All clients exhibit the same behavior. Please help me if you can. I have never had this issue at any prior company I have worked for. One more quick thing, it seems to affect Outlook 2013 as well. Thanks.