10.11, Mail.app Memory Leak?

I installed el capitan over min lion (so, skipped yosemite) as bit-rot was setting in on some apps. The install crashed mid way but fortunately a backup was available, made immediately prior to starting the process (time machine was used). The install completed and all the apps were updated. But mail induced nearly continuous beach balls. Also, there was an evident memory leak. I tried the least invasive moves first, and the beach balls went away after ~/library/containers-com.apple.mail (see prior post regarding this one) was moved and replaced (by a subsequent mail start). However, a memory leak became very evident after this and, *if* any file related email activity occurred, would accelerate, head past 1GB and eventually become unworkable. CPU load would typically top 100% as well (machine is a mb17 pro with i7 quad core, 16gb memory).

Watching how mail is behaving and observing the relationship between activity and memory growth confirms mail is broken. I am guessing that it's in the database-mgmt or mail-file-mgmt part of the application, since memory leakage really takes off if new files are grabbed (i.e., after deleting and re-grabbing IMAP files) or a file export is started. In time I've been writing this, memory has topped 1GB and is passing 5GB while IMAP files are re-loading (130K of them will load before it's over).

I suspect I can get by if I just restart mail periodically and avoid any file intensive activity. Starting from scratch with el capitate is a grim thing to consider, especially since it's not rational to expect that to fix a mail bug. If there's a good unix/linux mail app that turns out to have a good mechanism for importing apple mail files, that would be interesting to consider, in order to once again have a reliable mail app.

I recently updated my Macbook Air to 10.11.3. Instantly mail started to locate more and more memory until the swap space became too big and rendered the whole system unusable. Following the steps by epikeia I could pinpoint the problem to one specific IAMP account but the problem still exists once I add the account in question. The account in question is my universities main account hence I can not just remove it. The account has around 90.000 mails, though they are not in the inbox but stored away in an archive directory. I don't know if it is the size or one specific mail but I guess it is the size.

I also could confirm that it happens after the 10.11.3. update having two iMacs with 10.11.2 which do not show the problem. Once I upgraded one now to 10.11.3. mail on this iMac instantly started to show the same behavior. Hence, from my experience it is a problem showing up in 10.11.3 for an IMAP account with a lot of mails. That is how far it goes.

As so many here I am very disappointed by the slow response and lack of any support by Apple so far. Mail is for many people a mission critical application which most can not afford to not be working. My only workaround so far was to install thunderbird to get back to work after hours of trying to identify the source of the problem. So far, one of the main reasons I tell people asking me about "why a mac" has been stability and reliability when it comes to everyday tasks. This always was a solid reason to spend more money. This mail problem already ruined a weekend for me and I guess for many others as well. Such a frustration from a tool is the worst thing that could happen.

A small add-on, I don't know if it is related. The same upgrade to 10.11.3 causes more than the mail problem.

1) I just identified that the signatures I stored for usage with preview all have been removed.

2) All file open/save dialogue boxes displayed by application do not show the typical targets like home etc. in the left bar any more. The same was true for the basic finder windows but I initially did not link this to the update and just restored the missing targets.

Linc,

I am having an issue with Mac Mail after upgrading to Sierra. My mail, which is Exchange and Mac Mail, is showing a continual download of messages in the 10,000's. This is discussed in this thread Mail constantly downloading messages but so far no resolution. I wonder if you have one.