I have two accounts configured in Thunderbird. One of them isn't for a Gmail account and the other one is for a Gmail account. I've just made a backup of my emails from the first to the Gmail account. I have followed the guide help step by step. When the process has finished I had all my messeges in the Gmail account and I could read any of them, but the attachments were lost. So, I have made the copy again putting the emails in their original folder. After that, I can read the emails and I have access to the attachments. I've repeat this process two or three times and it happens in the same way. So, how can I make this copy (backup) without losing the attachments? Thanks.