How to resolve Slow Email Opening on macOS Monterey 12.4

I followed that procedure of unchecking “protect mail activity” and the mail appears to be working properly. Thank you.

update to Ventura OS. It's fantastic.

I just upgraded to the Ventura OS. The email issues have vanished.

Life is good!!

Same problem here. Monterey 12.5. I noticed you can speed things up if you click reply. It then shows the message from the sender without delay. But... you have then created a draft that - if you don't really want to reply - you will have to throw away later. Would be nice if Apple could come up with a patch, because this is very cumbersome.

This 100% is not an age of the machine thing. It is 100% a Monterey thing. My 2021 MBP16 with 64GB of RAM has this problem. I also have a 2012 MacBook Air and a couple 2015 Mac Book Pros that do not have the problem... but they're still running Mojave.

Already done that. The strange thing is... the first email you try to open will usually open right away. After that, the next mails become very slow. I now open all mails I want to read by double clicking them, so they open in their own window. Then I go do something else while they take their time opening.

Slow email message opening continues despite everything I have done on my iMac. Does not happen on iPhone or iPad. Happens some on M1 MacBook Air. Have tried everything to resolve it. Contacted my VPN provider - sent them all sorts of stuff. Don't think it is related to their software because I uninstalled it and same problem. Also contacted my antivirus and internet protection software vendor (Sophos), and they worked through a number of things and couldn't relate it to their software which they were in the process of analyzing for other issues. Anyway doesn't appear Sophos Home was causing problem. Checked with my Internet provider - really unlikely they are at fault given that everything else is working fine. So I installed Airmail program software and tried with it. Doesn't really happen with Airmail (but I really prefer Mail over Airmail program). Leaves me to feel strongly that this is some problem within the Apple ecosystem of Apple Mail and the Mac OS software. Since I hear many other friends who have Macs telling me they are experiencing the same problem with their Mail emails, one is only left to conclude that Apple itself needs to work on solving this issue. Am I asking for too much?

Those features are turned off on my machine.

What's weird is that I've been traveling for the past week and a half, and I haven't seen it get stuck once.

At home, I have two LG monitors that I also use as docking stations - they have USB hard drives attached as well as wired ethernet. They are daisy chained together via DisplayPort, and when I'm home I dock to these via a DisplayPort-to-USB-C dongle. I have never experienced the issue when disconnected from this setup.

As noted earlier, it's definitely not a network issue because FireFox is able to load pages when Mail is stuck. And sometimes Safari won't load content when in this mode. I still think it has something to do with WebKit which renders content for both Safari and Mail.app. And just googling I see that somebody else has noted this connection: Mail, Safari, Chrome and other WebKit-bas… - Apple Community

I am using MacBook Air from 2013. Mail is very strange !!! Sometimes you opened it and have 5-6 seconds you can see the mail content then on next letter it is white. You can see it by hitting reply or close open the mail. This is on version 12.6.2 latest. I have also the same MacBookAir from 2013 but with version 11. There are no such problems with the same mail account. So it is 100% software BUG ! Something is locking the mail client. Yes i have tried disable / enable / uninstall antivirus AVG. Also disable enable any kind of spam filtering / hide ip stuff. The problem still stays the same. Also Safari very often locks up the same way like mail client. Apple do something !

I actually had forgotten about this issue until I saw all these posts appearing again. The issue seems to have resolved itself on my Macs without me noticing. In my case, email slowness might happen a couple times a week, or a couple times a month. I can tell you two things that have changed with my system that may or may not have been a factor.

1. I deleted Little Snitch. There are so many services now that want network access, it because too much of a pain in the *ss to keep track of it all. I finally surrendered and gave up on Little Snitch and uninstalled it.
2. Due to unrelated issues with my email server, I deleted and re-added my email accounts on the Macs.
3. I am up to Sonoma 14.4.1, so maybe these had nothing to do with it and Apple pushed out some fix or other.

I don't know if either or the combination of these things did it, but I have not experienced slowness in months (knock on wood).

Lets wait & see how mail does in the new account after it's on equal footing as the Original account, nut if Mail then Performs well, my guess is the starting over on the Mail accounts in the Old aaccount is likely the next option.

Then boot into Safe Mode to run the fixes I described and then reboot normally and run for a while to see if the problem comes back. Safe Mode is really about the fixes run during boot.

This is not a fix, but if you want to see the content faster, click "forward" and you will see it in the forward window.