Running out of application memory

Today I have been getting this alert on my new MacMini with 16 GB of memory:

The outlier has been MS Outlook which was using over 2 GB! I quit that and restarted it and now it’s clocking in at about 360 MB. Does anyone have a clue what was going on?

In the absence of additional information, I would guess it is a memory leak in the Outlook application.

For those who don’t already know, a memory leak happens when an application allocates memory and later loses track of it, so it can’t use the memory and it can’t release it back to the system. When this happens, the only way to recover the memory is to quit the app, at which point macOS will reclaim everything the app was using.

As for what you can do about it, the first step I would suggest is to run Microsoft Auto update (should be on the Help menu of any Office app) to see if Microsoft has released any updates to Outlook, which might include a fix for the memory leak. The next step would be to check to see if Apple has released any macOS update, in case the memory leak is coming from a system framework.

If there are no updates, or if the updates don’t fix the problem, my next step would be to submit bug reports both to Apple and Microsoft. Be sure to include as much detailed information as possible about the bug, including information about the app and platform (hardware model/configuration, OS version and build number, Outlook version and build number, etc.)

Good luck.


Thanks, David, but I don’t think that’s what’s going on. I’m still getting that alert even when Outlook isn’t running or when it’s using a more normal amount of memory.

This is what I’m seeing in the Activity Monitor, now when I’m not getting the alert, and at other times when I am. Sometimes there’s a short red band amid the green, but the height of the graph never gets much above what this shows. So I don’t think it’s really a MS problem…I’m running macOS v. 11.4 on a Mac mini (MI, 2020).

Well, I restarted my computer (should have tried that right away, I know) and now the memory used is down to 9.45 GB. I see a couple of other things that might have memory leaks and will pursue those with developers.

The persisting question is, should I be seeing these alerts when I’m using around 75% of the memory? and actually right now App memory is at 5.98 GB, when it was 5.05 before. Compressed is now 875 MB as opposed to 4.29 GB.

Any further thoughts appreciated.

Just to clarify, what that graph shows you is that in principle you should be fine.

You have 16 GB of which 2.62 GB are absolutely required to be in RAM. Another 5.05 GB are in there too, but they could be swapped out if required. There’s some compressed memory (fine) and there’s a little bit of swap going on too (nothing dramatic). The cached files entry shows you that in the past some memory was used by some app and is now no longer in use, but macOS is smart enough to keep it around in case it needs it again (and because it thinks it doesn’t need that RAM for anything else right now—correct since there’s still ~3GB free).

The bottom line is that there is nothing in that graph that would show you are suffering from lack of memory. Keep an eye on page-outs (when you see swap increase). If you were seriously low on RAM, you’d see that figure start to go up a lot.

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