I have a problem with my Outlook 2013 appointments, the appointment window is visible in taskbar preview thumbnail but is otherwise invisible.
I'm running Office 2013 on Windows 8.1 Pro + latest updates. I did a "Switch User" in Windows 8.1 and left Outlook running in the original user account with an appointments window open. When I signed out of the second user account and logged back in to the original user account the appointments window would not come to the fore.
This is very frustrating as I can't create a new appointment or amend existing ones.
Disabling hardware graphics acceleration in Outlook 2013 hasn't helped.
Note for MSFT: This is similar to my posting here when the same thing happened with Reminders and Steve Fan kindly posted a solution:
https://social.technet.microsoft.com/Forums/office/en-US/f00e895a-15f8-4619-8545-6ac4ad40ec2d/outlook-2013-reminders-window-is-visible-in-taskbar-preview-thumbnail-but-is-otherwise-invisible?forum=outlook
It appears to be a bug in Outlook and very frustrating as I have no way of acknowledging reminders and they are just building up.