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Invizzible

macrumors regular
Original poster
Feb 9, 2003
223
1
Hi all,

I have just recently learned the difference between imap and pop, and could use some help trying to get my two Leopard machines to sync their Mail via Gmail imap.

I looked at my gmail settings and found I already had "Enable imap" selected. Then I looked at my two gmail accounts in "Mail" and they were both pop accounts. So in "Mail" I switched the servers they use to the imap servers. I noticed that they still say "Account type: pop" but I figure that is only a label and not a functional title (and couldn't see any way to change that to imap). So then I created the same two accounts on the newly acquired laptop (also runs Leopard) and made sure they were imap accounts right from the start.

This is where I got confused. When I pressed "Get Mail" on the second machine, it said it was downloading over 5,000 emails. I don't have anywhere near that many in my first computer's "Mail". I was under the impression that imap syncs the two "Mail" applications, so I didn't know what was going on. Was it downloading every email of mine on the gmail server? Is there any way I can avoid this? I have never deleted any of my emails off their server, so I have waaaay too many to put on my computer. I just want the two computers sync'd. Another weird thing is that in the second email account, emails were appearing on the second machine as unread, even though they were all read on the first machine. Aren't they supposed to show up as read?

I'm wondering... is it wrong for me to have changed a pop account from an imap? Should I have created new imap accounts in "Mail", and then deleted the old pop ones? And if I had done that, would all my mailboxes and emails get deleted or would they magically appear in the new accounts? I'm really worried about losing important emails, especially since one strange thing that happened during this process was all my emails in one account from Feb 11 to Feb 19 disappeared off the gmail server! If there is a fail safe way to do this, please give me instructions that a 5 year old could follow so I won't screw it up. Much thanks ahead of time to any of the very knowledgeable people on here who care to chime in!
 

annk

Administrator
Staff member
Apr 18, 2004
15,122
9,243
Somewhere over the rainbow
I'm interested in the answer to this as well. My problems using Mail 4.4 and Gmail on multiple Macs are slightly different, so I won't hijack the thread by listing them. But after googling around I see that many people are having problems with Mail and gmail.

I'm actually considering cutting out Mail entirely :( and using a different client, simply to avoid weird issues where gmail just doesn't work via IMAP with Mail.
 

annk

Administrator
Staff member
Apr 18, 2004
15,122
9,243
Somewhere over the rainbow
I've followed Google's instructions exactly for my machines running SL and Leopard, but the accounts still aren't syncing correctly and I know Invizzible and I aren't the only two because the gmail support threads are full of frustrated users. :( I've tried a lot of the supposed fixes people have suggested there, but nothing has worked so far.

To the OP: I just stumbled across this article. Haven't had time yet to read it carefully, but maybe it can help us.

Edit: I just went through the whole thing and did what it said. I had to improvise a little, because it was written for a version of Mail prior to 4.4. But as of now, all my mail seems to be syncing correctly. Hope it can fix your issues, too.
 
Last edited:

rcp27

macrumors regular
May 12, 2010
212
19
Right, got a bit of time now, here's the longer version.

It's helpful before we start to explain the key difference between imap and pop. On a pop account, your client downloads all new mail from the server and tells the server to delete the messages (though gmail ignores the delete bit, and still keeps a backup even if you use pop). The only copies will then be on your client machine. This is a bit of a pain if you have several machines (desktop, laptop, iPhone, for example). Imap, on the other hand, is designed so that the remote server contains a "master copy" of your full email account, and clients sync to it (a bit like having an iPod, an iPhone and an iPad all synced to the same iTunes library). This means that if you read a message locally, it should get marked as read on the server, but a copy is left there, so that when a second email client checks the server it finds the message still there, but marked as read.

On versions of apple mail before 4 (so the versions in Leopard), the default for a gmail account is pop, but mail 4.x (the version that ships with Snow Leopard) defaults to imap. Mail 3.0 can be set up to read by imap, though. Now neither gmail nor the mail app do pop or imap exactly as the basic idea above implies. The main difference is that for an imap account, mail will download everything and keep a copy locally as well as leaving a copy on the server (though iOS mail doesn't store a local archive). This means if you happen to not have an internet connection you can still access your mail, and if something should go wrong with gmail, you will still have a copy.

Equally, if you acccess gmail with pop, it will not actually delete your old messages, but it moves them out of the inbox and into the "all mail" folder instead. (gmail also handles imap folders differently, but that's not important just now.) An important distinction is worth noting here, that if you download a message with pop, gmail marks it as read and moves it out of the inbox when it is downloaded. With imap, gmail will not mark it as read until the imap client marks it as read (ie you read it) and the mail client connects to gmail to tell it to mark it as read.

So to migrate from gmail-over-pop to gmail-over-imap for a mail 3.0 client, the first thing to do is check that gmail has a full set of all your mail on its servers. The second thing you should do (as always) is make sure you run time machine, so that if it goes wrong you can roll back to the old version. Then delete your old pop account and create a new gmail account using imap according to the instructions on the gmail website.

Now what you will have is an empty imap mail account locally and a server full of messages. Your local account will then try to sync everything, which will include your "all mail" folder, your "sent mail" folder and "deleted" folders. This is the cause of your 5000 mail download. You need to let this finish, but it will only happen once (per computer you set the account up on). Once this is done, you have a complete local copy of your gmail account, so if something goes wrong, you have everything locally. Once this sync is done, on subsequent occasions when you check your email, you will only download changes.

Now the cause of your checked messages appearing as unread on a different computer is a bit more mysterious. What should happen is when you read the message, the computer you read it on should send a message to gmail to mark it as read. Then when you log on from another machine, it will download it (to keep its local mail pool in sync), but marked as read. When you read the message on the first computer, did you read it offline? If so, then the computer you read it on won't have been able to send a message to the server to tell it that it had been read. Note that if you connect with pop, the simple act of downloading the message marks it as read on the gmail server, but with imap it won't get marked as read until you read it locally and reconnect to the server to tell it that it has been read.

The mail app on iOS works a little differently because it only downloads a maximum of 50 unread messages (you can ask it to download more) and does not keep a copy locally (so it acts more like a "proper" imap client in that respect).
 
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