For different reasons I have many different Google accounts and wanted to merge them all into one Google Apps for Domain account. I also wanted to upload email from the past years to that account.

I’ve tried before to move a lot of messages between Google/Gmail accounts by just dragging the messages from one IMAP account into another (using a regular IMAP client such as Thunderbird or Mail), but it never works for a lot of messages. Then I found out about the Google Email Uploader tool, and gave it a try.

My first attempt was to use the Mac version of Google’s Email Uploader and just upload all messages I had downloaded in my local OS X Mail setup. The upload was supposed to take around 18 hours and I tried twice but both times, the uploader seemed to get stuck on some message(s).

I downloaded the source for the app and tried to figure out if I could patch the app to make the work easier. But instead of digging through all code, I thought I should give the Windows version a try instead. It has been around for a longer time and therefore probably a bit more reliable.

So I set up Thunderbird in my Windows installation (running VMware Fusion), and downloaded all messages from my IMAP server, and then uploaded them using Google Email Uploader for Windows. Everything went smooth and took about 20 hours.

For the next batch I imported the messsages into Thunderbird for Mac and then used the uploader tool for Mac. This time it worked great (but was fewer messages).

So, lesson learned: Try to import the messages into Thunderbird if the uploader get stuck when uploading from Mail.app. If that doesn’t work, try the Windows version.