To quit (close) a Mac app normally, choose Quit from the app's menu in the menu bar, or press Command (⌘)-Q. If the app doesn't quit, follow these steps to force the app to quit.
If you are getting problems in accessing MSG files in Apple Mail and want the best solution to read Outlook MSG content in Mac Mail. If your answer to these questions is yes then you have reached to the exact place now where we will explain best methods for opening MSG files in Apple Mail by converting them to EMLX format. Open MSG File on Mac via Apple Mail Save MSG to MBOX Download Mac MSG Converter and then Launch it. Click on the Add File button to add MSG files. MSG file is the single file format created by MS Outlook. There are several applications available on Mac with which users can view the MSG in Mac Operating. Some of these applications are: Kupon.BG Klammer, Mozilla SeaMonkey.
Press these three keys together: Option, Command, and Esc (Escape). Or choose Force Quit from the Apple menu in the upper-left corner of your screen. (This is similar to pressing Control-Alt-Delete on a PC.)
Then select the app in the Force Quit window and click Force Quit.
You can even force the Finder to quit, if it stops responding: Select Finder in the Force Quit window, then click Relaunch.
How to force an app to close on your iPhone, iPad, or iPod touch.