Mail constantly downloading messages

Hi:

In my case the never ending download was caused by 2 corrupted emails. Once I deleted them I did not get the download any more. I do, however, still have the high CPU usage... No solution for that yet, unfortunately.

You may want to have a look at this discussion for possible things that may help in your case:

https://discussions.apple.com/thread/7275988?start=0&tstart=0

Good luck!

OK, thanks for that. The corrupted emails - were they only in the MacBook Pro system or on the web server or both? My problem is only happening in my MacBook Pro using IMAP. Should I remove all email messages from the MacBook?

In my case they were in the server (I had Yahoo, also using IMAP). To figure out which emails were corrupted I first tried copying all mailboxes to my Mac; whenever there was an error, or the copying did not continue, I went and checked the individual emails that had not been moved from that mailbox on the server with the web interface. Eventually I found out the bad ones cause the web interface would not be able to open them.

As I wrote before, this solved the continuous downloading of messages, but it did not solve my CPU problem.

Good luck!

I think I also have solved this for my specific situation, here is my info if it is useful.

Symptoms: two mac's (El Capitaine) accessing the same account on POP3, from fasthosts (which is probably not relevant). Having the two Mac's is not relevant to the problem, they just both suffered from it and being POP3 there is no issue with 2 machines accessing the same account. 1 PC was doing 2 of 110 (which was the amount of emails in the inbox), then after a while went to 2 of 220 - and so on (note the multiple of the inbox contents). The other was x of x000's presumably because mail.app had been open for days. I am not saying this is the same as with IMAP accounts as the protocol is different, but it may help.

What I did:

• Turned off automatic email checking for each of the accounts in mail.app
• Right clicked each account and chose get mail or sync mail to see which one was getting stuck
• Tried the account deletion and physically deleting the mail box files in previous posts - no difference
• Went into web mail for that account and saw the number of emails related to the downloading message which gave some clues
• Sent a few messages from mail.app in that account to that account and saw them arrive in web mail. Did thee reverse i.e. send a mail to the same account in web mail, saw it arrive in web mail but not in mail.app
• Using Webmail moved all messages in the inbox to a backup folder that was not part of the inbox. I think this needs to be different for IMAP because it syncs all folders, so you might need to try and move them outside of sync'd folders
• reloaded mail.app all good, mails sent and recieved
• put them all back in the inbox, problem started again
• re-put them in a backup folder and put a few in the inbox - all good
• did this in small chunks while it was all good as I got nearer the bottom, I reduced the number transferred so I could isolate the offending email
• It turns out it was the last one, which when it was in the inbox, the problem happened, when I removed it the problem was fixed - I had an inkling this was the case as POP 3 starts with the oldest
• Problem solved can't see anything wrong with the offending email, but can't be bothered to check it deeply.
• Reloaded mail.app on the other machine and it was instantly OK

I hope that helps

I'll work on that, thanks.

Just to add, I have found that the constant downloading is happening on two Macs - my MacBook Pro running El Capitan and an older iMac running 10.6.8 - both set to IMAP, but the one iMac running POP, also on El Capitan does not constantly download. The constant downloading does not result in the mail seeming to actually go anywhere in either of the computers.

FYI;

You may find this useful:

I am using latest apple mail, with several gmail servers.

Those iMap created an "archive" folder and mirror messages there to, so I have "New" flags in several places.

Just fixed that, following how do i remove archive folder in mail?

So, I went to gmail-settings-labels and unchecked "all mail" "show in IMAP"

Two things happened:

1. The archive folder went away (Yay!)

2. CPU, laptop fan went berserk with mail reporting downloading of some 32,000 messages 😟

Your thoughts?

I too had this happen.

My solution?

Outlook for Mac.

And I prefer the functionality of Outlook over Apple Mail.

Hi Yairs et al, the symptom of the status of OSx Mail.app constantly "Downloading Messages" with non "new messages" is still manifesting itself at OSx 10.11.5 with several iCloud based mail IMAP based accounts on several of our machines.

IMO There's too much "bug-boo" and misinformation about a work around for this issue and therefore I have posted a simple set of instructions that we use regularly with clients to fix this pest issue.

To resolve this ICLOUD based issue you will need to remove several state information files and plists in your HOME directory ONLY and logout and login again.

Notes:

1. if you have emails that are NOT RESIDENT on any iMAP server, you MUST back these up or have them restorable from something like a TIME MACHINE BACKUP.

   the will be emails that are "On this Mac" - care here.. just copy hem somewhere.

2. the procedure described here work with OSx accounts (local and local network) that have tested from 1 to 17 individual IMAP email accounts that exhibit this issue described in this thread.
3. all mail structures will be refreshed from the IMAP servers.
4. for ease of completion , it is issued iCLOUD KEYCHAIN is employed to automatically provide authentication for all email accounts.

Here's a recommended procedure to resolve this issue at 10.11.5 with 100% IMAP based accounts .

Procedure

1. Have a completed backup of your ~/Library (home directory library) handy

   Time Machine backup or simply option+drag ~/library folder not your downloads or somewhere.

2. Quit your mail.app

   +Q

3. Sign Out of iCloud
   • System Preferences/ iCloud / sign out
   • take all the DEFAULTS (don't be tricky)....
4. Finder: Navigate to you home directory library where you will DELETEing these files and structures. Do any of these to access you home directory's / library
   • terminal > open ~/library or
   • Finder / Go / option key > Library or
   • Finder ⌘+shift+g ; type in ~/library and press return
5. Finder: Open Containers folder and DELETE com.apple.mail folder or issue the command below

   rm -rf ~/Library/Containers/com.apple.mail

6. Finder: Return / Navigate back to the ~/library folder and locate the Mail folder (don't open it)
7. Finder: Delete the Mail folder (move to trash or issue the command below) (remember you have at least one instance of this folder as above!)

   rm -rf ~/Library/Mail

8. now LOGOUT of your mac account (⌘+shift+Q)
9. now LOG IN (log back in) to your account
10. ensure you have a reasonable internet connection to UPSTREAM (the interwebs!)
11. Log back into (sign in to)  iCloud
    • System Preferences/ iCloud / Sign In
    • make sure Keychain is enabled - if necessary get authentication from other device)
    • make sure all the iCloud settings you want are ticked
12. Launch Mail.app .. then in Mail.app
    1. monitor the Activity as all the email accounts are set in the Mail.app UI (use ⌘+****+0)
    2. the emails are downloaded from the IMAP servers for each account... be patient
    3. you may need to customise you Mail.UI again.
    4. NOTE: for those emails "On This Mac" you will need to restore them from the backups above.

This resolved this issue for us and many of our clients .

Hope that helps.

Post your results for others to see.

Warwick

Hong Kong

Thanks. Perhaps this solves the issue of the continuous downloading of messages, but it does not solve the problem of Mail using large amounts of CPU. I followed the steps, but Mail keeps using 200% CPU.

For the record:

I installed El Capitan in a fresh new partition from scratch. I did not migrate anything from my previous installations, I did not sign in to iCloud, and did not install any other software, just EC 10.11.5. I started up Mail, connected to a single IMAP account, and waited patiently for Mail to download 65000+ mails from that account. After that, each time I check for new mails Mail goes up to 200% CPU.

I did the same with Yosemite (fresh install on a new partition, no other software, etc.), and there Mail behaves normally. CPU goes up to ~20% for 1 or 2 seconds, and that's it.

Something **is** different (and possibly wrong) in Mail in EC. Other mail programs in EC (e.g. Airmail, Thunderbird, Postbox) do fine. It is just Mail in EC.

It's very strange activity that thousands of mail are coming in inbox .

What about the settings if your are using IMAP account in mail preferences .ie port settings , in accounts > account information , mail box behaviours , advanced also in junk .

If we open mail app right click on inbox or click on triangle a window opens > click on info > the limit is 18.25 GB , is it exceeding .

Please post the settings .

It's very strange activity that thousands of mail are coming in inbox .

What about the settings if your are using IMAP account in mail preferences .ie port settings , in accounts > account information , mail box behaviours , advanced also in junk .

If we open mail app right click on inbox or click on triangle a window opens > click on info > the limit is 18.25 GB , is it exceeding .

Please post the settings .

Thanks for your reaction.

If I connect to a new IMAP account, Mail in EC has to download **all** the messages on the server. I have 62000 mails in 490 folders (not all of them in the Inbox), and it takes a while to download them all the first time. There is nothing strange on that.

The account info says I'm using 10.85 GB. (The provider does not limit the space available to store emails, so that is not a problem.)

I store Drafts, Sent, and Trash on the server, and Junk locally. (But I tried several combinations, and the problem is the same.)

The port of the IMAP server is 993, SSL is ON. All IMAP settings are as indicated by the provider. (And I use the same settings in Yosemite, but do not have this problem there.)

It seems that many mails that are on server or in inbox are malicious thats why they are creating issue .

If you delete the IMAP account and create it once again & bring back all mail they will again corrupt the mail box .

Is it possible if you save all mails in V3 folder, keep them for a day or two and try to create a fresh IMAP account & don't transfer all mails again in IMAP account .

So that it can be verified that malicious mails that may have embedded contents ( unknowingly ) will not corrupt the fresh IMAP account .

It seems that many mails that are on server or in inbox are malicious thats why they are creating issue .

If you delete the IMAP account and create it once again & bring back all mail they will again corrupt the mail box .

Is it possible if you save all mails in V3 folder, keep them for a day or two and try to create a fresh IMAP account & don't transfer all mails again in IMAP account .

So that it can be verified that malicious mails that may have embedded contents ( unknowingly ) will not corrupt the fresh IMAP account .