Issue – Apple Mail Moving Messages Stuck “I am facing issues with Apple Mail Moving Messages Stuck regularly. Recently, while working in Apple Mail, the indicator, which is there at the bottom sidebar, says “moving-messages” always. It never goes away, not even when mail re-starts. It seems Apple mail stuck on moving messages. Problems using your email accounts. If an email account is inactive. If a mail server rejects your login information. If Mail can’t connect to your email account. Free up storage space for email accounts. Mac Mail v10.3 (latest) keeps freezing on both my 2013 MacBook Pro and 2017 iMac, both running OSX 10.12.6 (latest). It happens once a day, and I have to Force Quit then re-start Mail (the message I'm composing usually gets lost).
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.
How to force an app to quit
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.
Apple Mail App
You can even force the Finder to quit, if it stops responding: Select Finder in the Force Quit window, then click Relaunch.
Mac Mail App Freezing Faster
Learn more
Mac Mail App Freezing Iphone
How to force an app to close on your iPhone, iPad, or iPod touch.