There may occasional bugs, but I don't know of any cases when Gmail actually lost emails. According to this talk [0], the bug referred to by that article caused

There may occasional bugs, but I don't know of any cases when Gmail actually lost emails. According to this talk [0], the bug referred to by that article caused some users' emails to be temporarily inaccessible, but all the emails were eventually recovered. [0]: https://www.youtube.com/watch?v=eNliOm9NtCM#t=1734 https://www.youtube.com/watch?v=eNliOm9NtCM#t=1734