Make sure the "Connection Doctor" window isn't open. Mail works fine until I open (and leave open) this window. Before long, Mail crashes and memory usage creeps up into the many GB range which eventually leads to an "Out of Application Memory" warning.
MacBook Pro 16″, macOS 15.1
While I am running Mac OS 15.2, I just tried to duplicate the issue and without the Connection Doctor window open Mail was using 160MB and when I opened Connection Doctor and left the window open for 10 minutes, Mail showed 157MB, so on my end that is not the issue.
I would suspect you have another process running on your computer that is causing a conflict. The best way to determine the process causing the problem is by posting the free EtreCheck report using the Additional Text option when posting. The report contains no personal information, but will not only identify the processes, it will also show the ones using RAM and CPU cycles causing the problem you see.
How to use the Add Text Feature When Post… - Apple Community
I will leave Connection Doctor open all day and report back tomorrow. I currently leave Mail open all day, so it will be an easy comparison. I just left it open for 10 minutes after reading your post to see if I could duplicate your issue and the memory actually went down in Activity Monitor. Just to confirm, I am not logging connection activity in Connection Doctor and if you are I would suggest unchecking that box to see if it makes a difference for you.
Restarting in Safe Mode is another good troubleshooting step that will prevent some third party processes from loading, but not all of them that would be identified in the EtreCheck report.
Update - I have left Mail and Connection Doctor open for the last 20 hours and have no memory issues. Using Activity Monitor, Mail is currently sitting at 178MB and I have seen it bounce around to a high of 180MB and as low as 155MB during that time. I have 6 email accounts added to the Mail app and received and sent mail from each one during that time.
I still suspect you have a third party process causing the problem and would refer you to my first post to use EtreCheck to identify what that could be. Make sure you are not using any of the know types of apps that have been seen to cause problems with the OS:
Do you have this issue in the first place? If so, try leaving Connection Doctor open all day (10 minutes may not cut it) to see if it crashes the Mac and then run Mail again without Connection Doctor open all day. I've had this issue since Ventura, but just discovered that the Connection Doctor window was causing the issue in Sequoia with the memory gradually going astronomical (watch Activity Monitor). I have no idea whether it would have affected earlier systems as I never closed Connection Doctor with the earlier systems while having this issue. Thanks for the additional info!
Thanks Mac Jim ID. Mail runs smoothly when Connection Doctor is not open, so I'm good. There are other threads in the Community that involve Mail/Memory Issues. Maybe you can try and find them and help them. I noticed Apple is locking a lot of older posts due to no recent activity, so it may be useless to do so. You'll find me sprinkled among a few of them from older OSs.
Sounds Good! It is not a bad thing that older posts are locked as a user should create a new post with any issue they have. Many times through OS updates advice given is no longer relevant and when there is not a response from the OP, it is likely they have just moved on and any further suggestions will be irrelevant as seen in many of the locked threads where there is a question to the OP that goes unanswered. When a question starts filling up with "Me too" posts from others who have not read what has been suggested, it makes it very difficult to provide the help that the original poster needs as the thread starts going in too many directions.
Not Logging. Thanks Mac Jim ID.
No problem, will update tomorrow.
Roger that. At first I was annoyed that older posts were getting locked, but you bring up several good points. Thanks again and have a great New Year!
Cheers!
Mail Uses All Available Memory Resulting In "Out Of Application Memory" Warning
