Hello This is a bit of an odd issue that I haven't been able to find a solution for. One of my colleagues communicates with clients regularly and we have noticed on two occasions recently that emails she sends out will contain an entire unrelated email thread as source just under the signature of the email. Obviously, this is quite a huge problem because sensitive communications with clients are being leaked. I can see the source-attached text when the problem emails get forwarded to me (in both outlook and Thunderbird) however, when we review it on her client, we can only see the problem on the replies from clients and not on her Sent Items. I have not been able to replicate this issue on my own or her client. It seems to happen randomly or for a reason that I can't determine. I've advised her to delete and reinstall Thunderbird hoping its just a problem with her specific one that's somehow corrupted itself. If anyone is able to give further insight into this problem, it would be great benefit. I might be able to provide more details/screenshots if requested but I'll need to go through and censor stuff first. Many Thanks