I recently had a client whose Microsoft Outlook window would not show. After using Windows System Restore a few times to fix it, i was forced to look into it further.
I discovered that something was causing it to go off-screen. Maximising it helped by using Task Manager, but it wasnt a solution and when not maximised, the problem was still there.
I downgraded to 32Bit office, to see if that would help but i still needed to get it back onto the screen.
Thats when I found this program which checks all running applications are within the available screen.
I repost if the 32bit downgrade didnt help.