13 Replies Latest reply: Dec 24, 2009 12:28 AM by Rich Daly
Erve Level 1 (10 points)
I would be very grateful if someone could explain to me why Mail seems to be constantly downloading emails - the activity monitor says "updating cache directory - sent my .mac account", although the particular mailbox varies - the activity viewer says incoming mail 1 of 1056 (for example). This seems to happen on a daily basis. I share this account on 1 other computer.

Surely it shouldn't need to do this so often? It doesn't really bother me except that I'm on the end of a satellite connection which, while uncapped, has low bandwidth, so this process is taking bandwidth from more important tasks.....

I'd appreciate any tips!!

Macbook Pro 3.06Ghz, Mac OS X (10.6.2), 4GB RAM
  • Golden Shoes Level 5 (4,015 points)
    It's because you're using an IMAP mail account, so the account is really on the mail server, with a mirror of it on your Mac. In order to keep them in sync, they have to communicate frequently and that does take time, depending on the amount of data to be synced and the speed of your connection.

    If you had chosen a POP account instead when you set this up, all your mail would be on your Mac, and this wouldn't be an issue at all.
  • Erve Level 1 (10 points)
    Thanks for the reply - I understand the principle behind IMAP, I just had no idea it would have to update the cache so regularly and for all the emails..... You'd think that it would only have to do it once , rather than having to re-update all the emails which are unchanged....

    Anyway, ours is not to reason why!!
  • Erve Level 1 (10 points)
    In fact, as we speak, Mail is re-downloading exactly the same mailboxes it did yesterday... Updating the cache.... Surely it shouldn't do this every single day for every single email in my mailboxes...?
  • Golden Shoes Level 5 (4,015 points)
    Surely it shouldn't do this every single day for every single email in my mailboxes...?

    I would hope not. You could disable updating the cache like this:

    Quit Mail if it's running.
    Go to Home/Library/Caches/Mail and delete the contents of that folder. Then use the Get Info panel to Lock that folder.
    Restart Mail and see if the problem continues.
  • Erve Level 1 (10 points)
    Interestingly, I don't have that folder.... Home/Library/Caches/Mail does not exist... I've looked in both the home folder and the root. I've even done a search for it - the only folder with Mail in the name is Mail Downloads....

    Perhaps this is the problem??

    Thanks again for your help!
  • Golden Shoes Level 5 (4,015 points)
    Hmmm…try creating that folder and not Locking it. Restart Mail, wait for the cache to update and then check that folder to see if anything is in it. If so,, then you could clear the folder and Lock it.
  • Erve Level 1 (10 points)
    Thanks for that - I'll try it and see what happens.....
  • Erve Level 1 (10 points)
    Ok, I've been watching this for the whole day and it seems to have worked...But weirdly....

    I created the Mail folder in Caches and since then, Mail checks the cache, but does not update all emails as was happening before, so that problem has been solved.

    However, what is interesting is that the Mail caches folder is completely empty...... Nothing in there at all..... Weird.
  • Golden Shoes Level 5 (4,015 points)
    Did you Lock that folder? If so, that's why there's nothing there; because Mail can't write to that folder. And since it's a cache file, Mail doesn't depend on it, so there's no harm in Locking it.
  • Erve Level 1 (10 points)
    No - I haven't locked the folder....
  • Golden Shoes Level 5 (4,015 points)
    Then it might be a mystery for the ages…

    But as long as it works for you and the problem is gone, that's the best news.
  • Erve Level 1 (10 points)
    Well as of this morning, everything is still fine - no more downloading of hundreds emails and no more random updating of the cache - it seems the problem is solved - thanks so much for your help!!!

    Certainly a mystery though......
  • Rich Daly Level 1 (0 points)
    I am having a similar problem to Erve.


    I wish to follow the steps outlined above & I have found the folder Home/Library/Caches/com.apple.mail
    Would this be the one to delete the contents of ('cache.db') and then lock?


    Message was edited by: Rich Daly