eM Client on macOS: Memory Leak?

After running 5d10h, eM Client takes actual 4,27GB RAM.

macOS Monterey 12.1 Beta (21C5045a), eM Client 8.2.1687 (bf522f0), MacBook Pro 2019 (i7)

Best regards

Now, after 6d12h, 5,13GB…

Moterey 12.0.1lient 8.2.1687 (bf522f0), Mac Mini M1
Configured 3x mail + 1x o365
After run 566 MB
after 2 day 725 MB

I have an Exchange account. Within this account I have subscribed to 3 shared accounts.

I will keep an eye on it until the final v12.1 of macOS arrives. Then the next reboot will be due.

In case it’s relevant: the MBP16 has 32GB RAM.

6,12GB after 7d10h runtime…

In the entire time, eM Client was actively used for maybe 1h.

This may be an issue that is resolved with the change to .NET 6 in version 9 (to be released next year).

There are some things you can do to reduce the memory usage until then:

  1. Restart eM Client occasionally.
  2. Open the About dialog and press Ctrl+J, which may free up some memory

Ctrl+J triggers a GC dialogue, but has no visible effect.

Ok, then just restart more often. That would have been my approach anyway, but I wanted to observe the behaviour for a while. :slight_smile:

Thank you.

Edith: 342MB looks much better. :slight_smile:

v9 has the same issue. I let em Client run for 2 days now without shuting down the computer and the memory consumption was 1,2 Gbyte on Windows 11. After an em Client restart it went down to 350 Mbyte.

Ive been using the latest eM client V9.0.1317 version on Windows 11 (build 22000.527) on 2 computers for a few days and running for a day only get average 220MB memory usage in Task Manager (even when eM Client is checking mail). When its idle only uses average 139MB memory usage.

I too also close eM Client of a night time and start new everyday.

The only thing i can think of maybe causing the high memory usage after a day for this issue (unless there is a build eM Client issue on Mac) that’s not happening on the PC for me anyway, is that eM Client maybe still synching all the remote mailbox to the local computer and just hasn’t completed fully caching all the mail folders so is very busy doing that constantly till completed.

but we’re talking about “eM Client on macOS: Memory Leak?”, so with the EM information on win11 you’re a little off

but we’re talking about “eM Client on macOS: Memory Leak?”, so with the EM information on win11 you’re a little off.

I suspect though when the official eM Client for Mac V9 is released or updated shortly you then “shouldn’t have issues on your Mac” if you say there are memory leak issues now.

Latest V9 Beta 2 for Mac if you want to test that is 9.0.661 Thursday, January 20, 2022. https://www.emclient.com/release-history

Have you sent in V9 Mac Beta testing feedback on that issue to testing@emclient.com?

If you haven’t send that feedback on email with your computer specs.

Lastly if you do test Mac V9 Beta 2 backup first via “Menu / Backup” along the time.

Same here… MacOS 12.4 Uptime: 17 Days, 22 Hours… which is nothing… It is just since I got “this” Mac.
Normal Uptime for my Mac is some months… 12GB for an E-Mail-Client… this is insane…


Pleased quit and restart eM Client. What is the result?

Yes restarting the em Client will fix this and memory usage drops to several hundred MB.
But overall that is not the point. The client should cleanup its garbage itself while running and not eat up memory of the whole system over time. Consider this behavior on Workstation or Server which has to run for month,… this can not be the way it should work…


Jumping in here because having the same issue.
I gave emClient a try and I liked it in general. But compared to Apple Mail, emClient takes a lot, A LOT, more memory (Apple Mail with six mail accounts configured: 359 MB | emClient with one account: 1,98 GB). This is more as my Photoshop takes and way too much for a mail client.
So I ended up removing emClient, unfortunately because I really liked it.

Suggest to try the latest V9.2.1222 for Mac and see if it’s any difference.


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What MacOS version are you using? Please try the latest version of eM Client if you have not already as suggested by @cyberzork and report back if the prior reported memory leak has been fixed or not.

If it still does not work, then try @Gary suggestion to see if it frees memory by trying this:

  1. Open the About dialog and press Ctrl+J, which may free up some memory

Report back your findings if the issue still exists or if hitting Ctrl+J from the About dialog makes any difference.

Hi @lancealot,
thank you for your assistance.

I’m running emClient 9.2.1222 on MacOS 13.0.1.
After the reinstall today, emClient “only” took about 1,10 GB if memory – wich is of course less than the 1,98 GB it took in my trial last week (also on 9.2.1222 i guess). Hitting Ctrl+J in the About dialog dropped the usage to about 0,9 GB.

That’s 1 GB difference to the inital reported value (1,98 GB in my last test), so great so far. But compared to Apple Mail (283 MB at the moment) it’s still sobering. And in Apple Mail there are six configured accounts with a huge amount of mails in each, in emClient I only configured one account and limited the mails to one week. So I assume Apple Mail has more to process but still uses much, much less memory.

So, it’s better now, yes. It’s now in a region around 1 GB memory usage which i also know from Thunderbird. So it’s not that bad but still not satisfying.

For interest: What does the Ctrl + J thing do?

@digitalbricks that is great to hear it improved, but I would watch it over time and see if the usage grows as you use eM Client over specific amount of time. I wanted to make sure you were testing with the latest eM Client version because version 9 uses .NET 6 which offers vast improvements over the Mono version that they had in version 8 of eM Client for MacOS.

The fact eM Client memory usage is close to Thunderbird on MacOS means at least it is keeping up with some of the competition. The most likely reason it is not going to match Apple Mail is because Apple Mail is programmed in native interfaces directly hitting the OS, while eM Client uses .NET as a framework that interfaces with MacOS. So due to the fact eM Client is a much more complex mail client then most and it uses .NET as the framework means most likely it will have some extra overhead when compared to Apple Mail.

What I can say is when I use eM Client on Windows 10 it is using 130MB of memory with 11 accounts setup. So it does seems more efficient on Windows, and since the MacOS version is newer along with .NET for MacOS probably not being as optimized then the Windows version, I can see why eM Client might not be as memory efficient as the Windows version. So at this time a higher memory usage might need to be something that is accepted on MacOS until eM Client can optimize it more, or Microsoft optimizes .NET for MacOS more (which it has done in the recently released .NET 7). The issue I would worry about the most is if the memory continually grows, which means a memory leak is present, which is something that is not normal and would need to be resolved.

I was curious also what the “Ctrl+J” does exactly, I just read it in a prior post. @Gary can you explain what the “Ctrl+J” does exactly, and if eM Client can be optimized for MacOS version more (such as moving to .NET 7) so it is more comparable to the WIndows version?

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@digitalbricks do you have an Intel or M1/2 CPU ?