Fixed: Mac Mail Won’t Quit & Keeps Interrupting Shut Down

I’ve been bothered by this issue several times. I couldn’t shut down my MacBook because of Apple Mail, an app that I use daily.

It seems Mail won’t quit and it shows me this error message:

When I tried to quit the Mail app, it just failed…weird!

Trying to find out the reasons why, I searched around and happened to bump into a few forum discussions where other Mac users were also experiencing the same issue.

And to my surprise, most of us (even the tech gurus) couldn’t figure out the exact reasons. 

Some say it’s related to the macOS version your Mac is running, while others argued it’s due to the Mail app itself — hinting it’s a bug that exists for more than a decade and needs to be fixed urgently.

Personally, I think it’s the latter. Because I encountered a few other issues related to Mail, such as the app taking forever to receive and send out new emails. 

Sometimes when I try to send out an email, it just freezes on the “sending” process, I have to double-check the sent box to make sure my email reply is delivered successfully. By the way, Apple knows this issue as you can see from this support article.

In another case, the Mail app had some problems after iPhone and iPad users updated to iOS 11. Apple and Microsoft were working together to fix the problems, as you can read more from this MacRumors report.

Now let’s get back to the topic!

The “Imperfect” Fix Solution

Anyways, the solution to fix the Mail app failing to quit error is simple. And there are several ways to do so.

First Method

Step 1: Click the Apple logo on the top left corner, then select Force Quit.

Step 2: Highlight the Mail app, and confirm the operation by clicking Force Quit. After that, your Mac should be able to shut down properly.

Second Method

You can also quit the Mail app via Activity Monitor, an app that allows you to monitor all active processes currently consuming resources on your Mac. Here’s how to do it:

Step 1. Open Applications, find Activity Monitor. Alternatively, you can do a quick Spotlight search on the top right corner to find this app and open it.

Step 2: Highlight Mail and hit the “x” icon.

Step 3: Select Force Quit.

Mac Still Won’t Shut Down?

I’m afraid the only solution now is to force shut down your Mac. You can do so by pressing the Power button for 5 seconds or so, and your Mac should be shutting down in a few seconds.

• For MacBooks: the Power button is on the far right side of your keyboard. 
• For iMacs: the Power button is behind the lower left side of your iMac’s screen.

Why It’s an Imperfect Solution?

Because there’s a possibility that this could corrupt email files, causing data loss. If you deal with Mac Mail emails on a daily basis, chances are there are a lot of email files generated.

Make sure to use the Force Quit solution with caution. And remember to back up your emails regularly just in case. 

That’s all for this post, I hope you find it useful. And hopefully, the Apple Mail team can improve the app and fix this Mail app bug.