Dear all, I've noticed a similar, rather serious problem with Thunderbird, first using it on MacBook Pro, now using ThinkPad with Windows 11 Pro. The Thunderbird used is 102.6.1 (64 bits). The problem: a mail read and moved from Inbox to another folder, gets overwritten by another mail saved in the same folder. Overwritten is only the content, while in the list of mails in the folder the sender, subject and date are still different. Overwriting does not happen when either of mails is moved to the destination folder, but at a later time. I don't think I can reproduce mail management that I did at the time the error happens, however I do not think I did anything strange. It is true that my email structure consists of around 100 folders with thousands of emails (unfortunate byproduct of my job description). I guess I do not need to state how serious this potential bug (or my mistake, perhaps...) is. The first time I attributed it to a perhaps non-perfect compatibility of Mac version of the Thunderbird with its OS, however the error being repeated at two different systems rules this out. Clearly the suggestions (or requests for further info) are welcome. Best regards, Bostjan Golob