The cause for the issue is unkown, but sometimes the Outlook window disappears completely, so you cannot see it at all, or the window becomes so large that you neither can move nor resize it with the mouse.
The simple utility ResizeOutlook neither must be installed nor registered. Launch the tool when Outlook is already started. Then it can fit the Outlook window to your screen by a button click, so you'll get back full control over the window.
|With Category-Manager you can group your Outlook categories, share them with other users, filter a folder by category, automatically categorize new emails, and more. You can use the Addin even for IMAP.|