I had tried to sync my GMail account once-upon-a-time, but decided it wasn’t worth the potential hassle. What hassle, I don’t remember– but in any event, I remember it was extremely easy to get it up and running using POP. However, this time around I decided IMAP was the way to go. Over the last few years I have slowly devolved into someone who uses GMail as my big e-mail cloud in the sky– that is, I want to be able to access an identical account (same inbox, sent, drafts, etc.) from anywhere (Macbook, PC, office, iPhone). IMAP should give me that ability.

Well, once I set up Mail to play nice with my Google account I noticed signficant slowdowns. I mean really, really slow. Like sending an e-mail that said “hello world!” took five minutes as the Apple pinwheel spun frantically. It seems like this a common occurrence with Mail 3.x and Leopard/Snow Leopard but there seem to be very few answers. I did end up finding one in the dusty corner of the internet.

It appears that Apple Mail has an issue with big attachments. I mean really big attachments. Like 20 MB big. Get rid of them, and it solves the problem. How do you do it? Well, there are two ways…

The easy way (tested by yours truly):

1.) Delete your IMAP account from within Mail by going to “Mail” -> “Preferences” and then clicking the little minus button below the account names. NOTE: I’m pretty sure this is foolproof with IMAP, but please, please make sure you are not deleting your e-mails from the server when you download them to your computer, because if you do that and then delete this account, well, you’ll lose your e-mails.

2.) Go into finder and delete the folder ~/Library/Mail/IMAP–/ or thereabouts.

3.) Go back into Mail, click on “Mail” -> “Preferences” and then the plus icon. Create your IMAP account as you did previously (make sure “create my account automatically” is unchecked or you will end up just creating a POP account with the default settings). This time, unclick “bring this account online” at the end of the creation process.

4.) Go back into “Mail” -> “Preferences,” click on your GMail – IMAP account, then click on the advanced tab. Uncheck “compact mailboxes automatically” and MOST IMPORTANTLY set the offline viewing preference to keep “all messages but omit attachments.”

5.) Set account to “online” and Mail will re-download all your e-mails; however e-mails and e-mails alone– no attachments. Everything should be running at Mach speed again.

Now, this way has one main drawback. You aren’t storing any attachments on your within Mail; if you want to download them, you have to do so as the e-mail comes in. This isn’t a problem for me, since I download the attachments I feel are important to whatever folder they are needed in by default and therefore don’t need another copy clogging up my inbox. However, if this is of crucial importance you can try the next step (at your own risk).

The hard way (I haven’t confirmed this works, but this would allow you to keep most attachments offline; only the ones over 20 MB are deleted– courtesy of bebopper):

1.) Quit Mail (Force quit if you have to)

2.) In Finder, click “Go” -> “Go to Folder.” Type the following folder path (replacing with your GMail User Name): ~/Library/Mail/IMAP–/.OfflineCache

3.) Look through the cached messages in this invisible folder and see if there is one or more larger than 20MB.

4.) Drag the offending large messages to the Desktop or Trash. Restart Mail, and Mail should stop hating you.

Both of these are essentially band-aids, so hopefully Apple will get its act together and figure out exactly what is going on. This seems to be a problem that has arisen in later incarnations of 10.5 and into 10.6, so it’s something that should be of pressing importance to the development team as we speak.