Mac Mail Constantly "Downloading Messages"

I have had a very similar issue... across 3 computers (2 x MBP and one iMac), we have had mail constantly downloading since late November 2017. I reported this to Apple on the 4th of December 2017, and after speaking with many support staff at Apple Care, we still as of today (23 Jan 2018) don't have a solution.

For us, it's having a financial impact as we are going over our data allowance as we are using wireless 4G in our office, and in Australia, these are limited... you can't get limitless data with wireless 4G here. So far it's cost us about $80, but if it doesn't get resolved, it will cost us much more. Plus it's cost us the time we have spent trying to fix the issue with Apple. The issue is, Apple doesn't know how to fix it, otherwise, we wouldn't be here talking about it almost 2 months later.

For everyone's information... Apple tried to insinuate that it was a Google (Gmail) issue... I then discussed this with Google and they said that it can't be and gave me a number of reasons why it isn't their issue. The one thing that they told me to do to isolate the problem was to use the same accounts on a different mail client, and if the problem did exist after doing that, then perhaps the issue may be with Gmail and the settings. So I did the exercise and put all the accounts into Outlook for Mac... After spending about 24 hours syncing across all accounts, Outlook was stable. I then had both mail clients running for a few days and took screenshots of the activity monitor to show how much data was being used by each program. And I mean I took a lot of screenshots... close to 60 over a week. This proved the issue was with Apple Mail and not with Gmail.

After doing all this, I was told to delete all accounts from Apple Mail and to reinstall them manually (without the Google prefixed settings). I did this and again after it fully synced, we keep having the same issue.

So 6 days ago (17 January 2018), I again contacted Apple via email asking for them to call me or respond to my problem, but as yet, I have not had a reply.

Does anyone know what's going on? lt's obvious that Apple doesn't know how to fix this right now, so I guess I'm reaching out to the wider Apple Community.

I'd be grateful for any advice.

Thanks 🙂

I've just got off the phone to the ACCC (Australian Competition and Consumer Commission) and they have said that if anyone has these issues to report the issues to them (ACCC). Essentially, they will then try and push Apple for a remedy. Worth a shot.

Hi again to all,

I have done a lot of work trying to solve this and have finally done so.

I had wiped my hard drive and installed Sierra, NOT High Sierra. This was on the advice of a Senior Apple Support person. But this did not work.

I then went to my server, as I have gmail accounts, and I decided to delete all my MX files and then redo them (my backend has an MX File "Wizard" - which automatically puts in the required settings into each field).

It took a couple of days for the settings to become live, but when they did, it solved the issue. I am no longer downloading tons of emails.

So that was what worked for me. I don't know if it had anything to do with High Sierra, as it may have just been a coincidence that all this happened with the upgrade to Hight Sierra on 3 computers. But something must have changed... I'm not sure what.

Anyway... I'm all happy now 🙂

I hope this helps others.

Good Luck!

MacBook Pro. Since High Sierra 10.13.2 and now 10.13.3. Mac Mail is constantly “Downloading Messages” often 30,000 or more, each time.

Constantly taking up more of my 1TB flash drive. And exceeding my monthly 50GB of internet allocation.

Actual mail size 35GB.

Gmail Drafts size: 214GB

These Mail Drafts folders are the ones being constantly changed/added to, during the “Downloading Messages” operation:

I had this problem, too. (Several Gmail-Accounts in Apple Mail.) What helped:

- Logged into Gmail web interface for the account(s)

- Opened "Drafts"

- Marked them all

- Removed the drafts (the actual mails stay intact)

If there are a lot of drafts you have to repeat the last two steps several times. This seems to have fixed the "constantly downloading" issue for me.

Also interesting: The drafts folder is kept "clean" since then. No more old versions of mails I already sent.

I was experiencing this issue as well across four machines in my office. Over 30GB were unnecessarily being downloaded daily. Neither Apple nor G Suite (email provider) support was able to offer any meaningful solution.

What I eventually discovered was the issue is linked to the setting under mailbox behaviors to store drafts on the server. Changing this to store drafts "on my mac" and restarting Mail resolved the issue for me. I hope this is useful to others suffering from this issue, of which there seems to be many.

I'm not sure if this is an issue with G Suite or with Mail, or maybe a combination of both. Interestingly personal gmail accounts don't seem to be affected. Regardless it was incredibly frustrating to deal with considering email working properly is one of my most basic expectations from my computer/email provider.

Thanks AaronA36. It appears that my issue is the reverse of yours. The drafts are on my Mac (>200GB of drafts).

This started happening immediately after upgrading to High Sierra.

My actual Mail size is 35GB.

The gMail drafts on my Mac are located here:

Seems to have worked: Logged into Gmail web interface and clearing the draft messages seems to have worked for me. I had hundreds in there.

Previously, I was getting about 7000 messages constantly downloading previously over the last few months. FYI

I have MacBook Pro with MacOS Sierra 10.13.3. Gmail, Yahoo Mail all viewed through Apple Mail client.

I have now eliminated the constant downloading messages completely, by logging into Gmail web interface and clearing the draft messages. There were hundreds in there. (Thanks spud2911).

However, on my MacBook, there is still 260GB of Gmail drafts accumulated during "downloading messages" since going to High Sierra.

High Sierra has not yet removed these "drafts", and I don't want to do it manually, as I don't want to cause further issues. Can anyone tell me how to remove them without causing further issues? I need the 260GB to be freed up.

They are located here:

Also having this problem with Yahoo Account in Mail with my Macbook Pro 10.13.3, High Sierra.

I was actually installing the yahoo account when this started, then I went to check my other Mac and there was with the same problem, always downloading emails, thousands of emails non stop. I thought it could be because of iCloud but the Mail program was not included in iCloud, I didn't do it because it would take too much space on the server and I didn't have that space. No extra storage.

Conclusion, I have been busy for about 3 days for many, many hours doing research on google to find a solution, so far nothing worked, it was messy I can say! I managed to stop the downloading but then it wouldn't receive email, only send. Also had the situation that it would stay offline giving Authentication Failed, had Login Failed, etc...........

Now back to the start. Mail still downloading...........

I wish I had an answer for this problem.

On my old MacBook Pro from mid 2010, with the Mail Program off, I could find the file MessageUidsAlreadyDownloaded3 and delete from the folder Mail in Library. Exact location was in the Home folder: Library/Mail/V5/MailData/MessageUidsAlreadyDownloaded3.

Now on my new MacBook Pro I don't find this file to delete, not in V2, neither in V5..... 😟

This has been an on-going issue for me on my Imac for a couple years and it seemed to resolve when I switched to a MBP... then it popped up again several months ago. I ended up switching to Airmail from Apple Mail and that the took care of the issue. I do not run/had never run Gmail or the likes through my Apple Mail. I do run Exchange (off of our Company server) for my Apple Mail.

One temp. fix for this known and pesky issue in Apple mail for me was to run the Rebuild option in Apple Mail.

Good luck!

Hi Drah123,
I think I found a solution.

I believe the issue was stemming from my Iphone- and my computer syncing.

Once I deleted my Gmail off my Iphone and re-imported it everything seems to be okay.... for now.

I have this problem too. Tried all the usual deleting of Gmail account and restarting it. Just won't stop downloading messages no matter what. Also wiped my iMac and started completely fresh with High Sierra. Problem still there.

Interestingly enough, I'm sure it is NOT Gmail. On my iPad and iPhone the messages aren't downloading over and over. And if I delete messages on my iMac it doesn't sync to my devices. So I'm 99% sure it is a High Sierra problem.

Doesn't happen with iCloud, or Outlook, through Apple Mail.