Outlook will not quit

Outlook will not quit since El Capitan was recently installed. cmd/alt/esc is the only way to Force Quit. I do have SpamSeive installed, but it hasn't been a problem before. When trying to quit, the main screen closes but the small secondary window asking if you want to delete the deleted items will not respond. Even the computer will not shut down until Outlook is closed. I would be grateful for any help/suggestions.