I have several email addresses being managed by Thunderbird. Occasionally one of my out going messages gets it's 'reply-to' address over written by one of my other addresses. So I'll send an email out from one address, but the recipient replies and it comes back to me on the incorrect address. It's always the same address that it gets overwritten to, but I never know when it happens. I have tried individually setting ALL my managed addresses with their own 'reply-to' and it still happens. I can never tell when an outgoing message has been overwritten or not, as it always looks correct at my side. I only know when a reply message then comes back into the incorrect address. This may not sound important, but it's infuriating because, for example, I'm monitoring one address for replies and I don't get any, but then later I look down at the other address and there's the reply there. I have tried removing the dominant address from Thunderbird and re-installing it...twice. I can't leave the entire address off Thunderbird, because I don't want to miss any emails that do come to it. Please can you offer some advice.