I’m running High Sierra on a 2016 MacbookPro. My business account uses G Suite (Gmail). I use Mac Mail and sync to my business account. I have a few other email accounts but my business account is by far the biggest.

I’m running out of drive space. I currently am showing 50GB space remaining on the 1TB drive in this Mac. Mail is the biggest user of disk space, with /Library/Mail taking up 160GB of space.

I’m trying to free up space but I don’t seem to be doing a very good job of it. I have tried Erase Deleted Items, which got me a little. I created a smart mailbox for email with attachments that is older than 5 years, and am using Remove Attachments but it’s a slow process. If I try to do more than about 500 emails at a time, Mail crashes. And removing attachments from 500 emails takes quite a few minutes. I have about 30,000 emails in this smart mailbox so it’s going to take a while to go through all those, and I’m not even sure this is the best approach, because it doesn’t seem to be having much of an effect on disk space so far.

One thing I notice inside /Library/Mail/V5 are what appear to be two “accounts” (folders with letter/number names) that both are large in size. One is 81GB and the other is 72GB. Looking inside those, the smaller one appears to be “On My Mac”. It’s full of folders of filed mail (I am a filer. Everything I get that I want to keep gets filed according to client/project/etc.) The larger one contains several subfolders, the only large one of which is [Gmail].mbox, which contains All Mail.mbox.

I am pretty sure that is syncing “All Mail” from Gmail, and I think the problem is, because I am a filer, I end up with two copies of many messages: One in On My Mac and one in the Gmail Archive or All Mail folder, which is getting synced down to my Mac.

It seems if I could get rid of All Mail on my Mac I’d immediately free up 81GB of space. I don’t want to get rid of All Mail altogether. It’d be good to keep it around at Google in case I miss something. But I would like to not sync it down to my computer. I still need my inbox, and other Gmail functionality to work, but I’m wondering if there’s a way to stop syncing All Mail to my Mac. And, if that’s even a good idea.

I also see the option in account settings for Download Attachments, with the options All, Recent and None. I read that Recent refers to messages up to 15 months old. If I switch to Recent will that update the synced All Mail folder to remove older attachments on my Mac, or would I still need to manually remove them? This presumes that the attachments are the bulk of the issue.

Any advice will be most welcome - thank you!

  • 81GB of mail??? It sounds like you’re using mail as your method of document sharing and storage. Have you thought about using Gmail’s cloud drive to share links instead of moving copies of the same docs through mail? My wheelhouse is O365 not Google, but I’ve seen and solved the same problem using that environment
    – Allan
    Aug 2, 2020 at 23:03
  • That would be nice but I can't control how clients choose to send me files. When they are sizeable I usually get them to use Dropbox or another means, but if someone's sending me a PDF, or I am sending them one, or an image or two it's more trouble to get them to use some other method. It's really just a matter of sheer number of emails. Most attachments are small I believe.
    – Bob Meador
    Aug 3, 2020 at 1:41
  • Part of its work flow. We have a policy that emails aren’t over 10MB. if they need to share a file, they can send Dropbox links or you can provide a shared space to upload files to. We do this with OneDrive all the time. Don’t Put the burden on you
    – Allan
    Aug 3, 2020 at 1:47
  • Most of my attachments are relatively small, just accumulated over a long time. Good to think about ways to reduce the problem in the future but I'm dealing with the space issue right now so for now I want to focus on what to do about that.
    – Bob Meador
    Aug 3, 2020 at 3:42
  • You either get a bigger drive or start moving those attachments to shared cloud space. You could delete the account, change your download settings and then add the account back. apple.stackexchange.com/a/392220/119271 It’s a fix for now, but you need to come up with a better work flow.
    – Allan
    Aug 3, 2020 at 5:23


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