Every time when I minimize Outlook, it closes.
How can I keep Outlook open when I minimize it?
Are you sure it closes?
Outlook has the option to minimize to the Notification Area (in the bottom right corner next to your time).
Hide when minimized
When Outlook is running, you'll also see an Outlook icon in the Notification Area. Click on it to bring up a menu and to toggle the option “Hide When Minimized”.
If you don't see the Outlook icon in the Notification Area after starting Outlook, the icon might be set to hide. Press the expand (upward “<” character) button at the left side of the Notification Area to expand it and show all hidden icons as well.
Extra Tip: If you sometimes accidentally close Outlook by the X in the top right corner instead of minimizing it, you might want to read the Quick Tip; Prompt before closing Outlook or minimize instead.
Disable “Hide When Minimized” for Outlook in 3 clicks.