Mail constantly downloading messages

I think I may have my problem fixed, but I did a whole bunch of things so I can't say for sure what exactly fixed it.

What I did was, I deleted ALL my e-mail accounts, not just the problematical one. Then I deleted the V2 and V3 folders. Then I did a Spotlight search for "mail" and included system files. I then deleted all mail plists and caches.

I then empty the trash, restarted and recreated all my e-mail accounts for scratch, one by one.

Also, I changed Check for New Message, which had been set to every 5 minutes, to "manually" and turned on IDLE command on all accounts.

So far, so good.

I just want to share, I have exactly this problem. Have been trying to solver for months. I have two Gmail accounts and one iCloud account. I'm presuming it is one of the Gmail accounts causing the problem.

Plan on trying some of the ideas here, in particular John Strungs solution.

What I hate is this issue while using WiFi during airline flights... just suck bandwidth, and I believe the airline provider then notices heavy use and then throttles my connection. have notice WiFi on airline is fast at the beginning, but later in the flight my connection *****!

wes

I can confidently now state, that none of the solutions have solved the problem for me yet. I'm not sure what to do at this point. Considering signing up for Office 365 to use Outlook on my mac if I can't get this sorted out in the next few days.

tried everything myself no luck. i have a .me account, gmail and go daddy accounts. 10.11.2

Same problem - constant 'Downloading Messages' but the numbers do not change. As of now, some 8,000 messages claim to be waiting to downloaded but they never come.
My problem is that I am in Uganda for the next few weeks and have a very limited network access. The re-boot took many hours and I have neither time nor airtime enough to do it again. My guess is that this is an Echange/Mail issue that will have to be worked on when I am back in office.

But surely it should be possible to correct Mail behaviour without a reboot???

The problem seems only to be connected to my Exchange account and started after a clean install when my MTN dongle software conflicted with El Capitan and crashed my MacBook (another story).

I have the same problem but only with my GoDaddy email account. I wonder if this has something to do with the GoDaddy's server itself rather than the app

I may be totally wrong here, but after struggeling alot with this problem and IMAP server connection failure + Mail crashes I

would suggest you try to UN-check the IDLE function, and change setting in the "Look for mail" to "every minute"

instead of automatic. More here: Recurring IMAP connection errors

My problems are solved now thanks to the combination of deleting V2 and V3 completely and unchecking the IDLE function.

It just works now. No zillions of emails non stop downloading, no server disconnection, no Mail crashes. 3 days and counting...

@Maksoud - I was having problems with a GoDaddy account too, but I had several other GoDaddy accounts on the same computer which worked fine. As I mentioned in an earlier post, I solved the problem by deleting both the V2 and V3 files and all mail plists and re-creating all my accounts from scratch.

@henkony - I think that setting "Look for Mail" to "every minute" may be counterproductive. I seem to recollect reading when I had the same problem several years ago that it could be caused by checking mail too frequently. If the client checks for mail before the previous download is completed, this can cause a synch problem which will precipitate a re-synchi.

My current settings are to check Mail manually only and IDLE is on. I seem to get mail fine now without having to check mail. The IDLE command pushes mail from the server instead of the mail transfer being initiated by the client.

@maksoud: I do not have a GoDaddy account, just an IMAP account, and I do have the problems.

@john: I will try your suggestion this week, when I am connected to the server (at my work) via an ethernet cable. Otherwise I will saturate the wifi connection at home when Mail wants to download all emails again.

@John Strung - You might be right regarding the first run after re-build, in that case I would still test to uncheck IDLE and set to get mail manually to make sure download first is completed before any new get-mail attempts are made. Could be worth at least trying...

The IDLE on is definitely a problem for me and my IMAP host (one.com). Been using IDLE on prior to El Capitan without any problems. Ever.

As soon as I turn IDLE on now, I get random server disconnections (every hour), weird everlasting connection attempts often followed by Mail crashes 7-10 times a day.

What I understand, In Capitan, Apple has changed the security protocol around IMAP, and it looks like many external hosts have a problem with this?

In my case it seems to be working perfect when Mail is making the request (IDLE OFF) - and not working when my IMAP server is poking Mail (IDLE ON)

So I'm just saying: Total re-build and IDLE off was the solution for for me.

Hope you guys soon find a work-around! Even better: Hope Apple is fixing it. Soon!

I also do NOT have a go daddy account... just one .mac and two .gmail

I still have this problem

I too have the issue. I've rebuilt, deleted etc. and it hasn't fixed it. It doesn't do it on my MBP but does on my iMac, both running the same OS version, both set up for identical accounts.

It's driving me nuts - I see it reporting that it is downloading 5 messages or so, for an hour; the messages are already downloaded sometimes and often other messages have downloaded since. Sometimes it gets a bit better but ultimately comes back. Mail is sucking up masses of CPU cycles doing absolutely nothing and obviously that affects other apps.

Apple appear to be ignoring, or unaware of the issue and/or this thread.

OK, so I just fixed this after having another look at it. As ever, YMMV and it could come back again but right now it has immediately sorted it for me. Basically, I have Avast Security (Free) installed. I disabled the mail protection in the prefs and quit mail. I then fired Mail up again and it downloaded a load of "stuck" messages, then the activity viewers no longer showed it constantly downloading mail.

If this is simply coincidence, then maybe it will all go pear shaped again shortly but for now it seems OK. There are a bunch of options within Avast to control what it does with Mail but I'm too buy right now to do a load of testing to see which one, if any, is the issue. Either way, it seems fine right now. I'll report back if it falls back into old ways.

Interestingly, Mail's behaviour has changed. Instead of being stuck, the activity/status window still shows it checking and then reports "no new messages", then closes the connection as it should. It does check really often though, and it's supposed to be getting messages pushed through - Weird.

For those of you who don't have Avast, I hope you manage to sort this. It is worth checking to see if you have any Mail extensions installed, especially from old installations or anything else which might somehow interact with Mail, I suppose.

Hi John:

Are things still working fine after a few days? I tried your suggestion but it did not work for me (too bad...) It may be that I did not delete all the plist files that you deleted cause I am not sure which ones are those... Anyhow, thanks for the advice.

Mariano