Transferring email archives from a account to a Google Apps account - alternative method

posted 22 Sep 2009, 05:46 by Anthony Horton   [ updated 25 Sep 2009, 07:53 ]
In my last post I described a method for transferring user data (emails, contact and calendar events) from a account to a Google Apps domain based account.  I used POP3 to copy all my emails from my account to my account.  This was simple and quick but had the big downside that it didn't preserve the labels from the original account so I had to manually relabel all my mail.

There is another way of transferring your mail that does preserve labels and is also fairly simple, however in practice it's likely to be a frustrating and time consuming affair.  The process is as follows:
  1. Make sure both the and Google Apps accounts have IMAP access enabled (check under Settings > Forwarding & POP/IMAP > IMAP access)
  2. Configure a desktop mail client (e.g. Thunderbird) to access both the and Google Apps accounts.  Over IMAP your labels will appear as mail folders.
  3. Use the desktop mail client to copy your folders of email from one account to the other.  As folders and labels are (more or less) the same thing this will enable you to copy all your mail from one account to the other while preserving labelling.
In theory this sounds great, however in practice IMAP does not appear to be a reliable way of transferring large number of emails.  If you try to copy everything in one go it will probably choke part way through, and you'll have to work out how far it got and start again from the last email that got through successfully.  How many emails you'll be able to transfer in one go will depend on the quality of your internet connection, the size of your emails and attachments, and possibly the mail client you're using for the transfer process, but with a large archive you could be in for a long, tedious job.

The same approach can of course be used to transfer email from any other IMAP enable account to a Google Apps/ account in a way that preserves existing folders/labels.  I'm currently in the process of copying several gigabytes of email archives from my work email account, however with the slow external internet connection at my place of work I'm finding I'm unable to reliably copy more than about 15 emails at a time.  It's fortunate I'm not in a great hurry to complete the transfer so can afford to do it bit by bit over the course of weeks or months to avoid getting too frustrated by it.

Update 26/09/09:

I've found that with a less execrable internet connection mass email copying via IMAP does work a lot better. I've got around the bottleneck of my employer's appalling external internet connection by taking advantage of Thunderbird 3's mail sync. While at work I allowed Thunderbird to make copies of all my important email folders to my netbook, and then took it home where I could copy my mail to my account using my home broadband connection. I have a fairly ordinary ADSL2+ connection at home, I'm a fair distance from the exchange so the bitrates I get are towards the lower end for connections of this type, and yet I still have connection speeds over an order of magnitude faster than I get at work. With this more solid connection the IMAP email copies are not only much faster but also far less likely to choke an a large email attachment, allowing me to copy an entire folder at a time.