It’s been a while since I switched back to the macOS default email client. I’m rarely shut down or restart my mac, so I didn’t know when the mail app super slow to start until recently I restarted my mac.

It takes minutes to show the window. No color ball, no dock bouncing. However, once the window shows, everything is back to normal. I tried to search for some answers but most ppl say creating a new system user or rebuilding all the mailboxes…. annnd its not working. The mail app is still slow to start.

I found this post at the beginning, and nothing helped but when I went to page 2, something looked promising, refer to this post, it worked.

Solution

So basically, there was an event id that was too old. This makes the mail app do tons of internal event updates during the start process. (However, this should be processed on the background thread tho.) Anyhoo, we just simply delete the file that stores the event id. This makes the mail app create a new record file in the same place with the new event id, and now the mail app starts instantly.

File path: ~/Library/Application Support/Mail/Plug-ins/Bundles/Library/Mail/Bundles/Properties.plist

Limitation

Yeh, it’s not a perfect solution. As you can see, events happening, so the id will grow. So as the new events keep coming, the mail app has more stuff to do before finish the start, at that time, you will need to delete that file again to make the mail app update event id.