I got a new computer in August and re-installed Thunderbird. I needed to search for an old email today and realized that there is a gap in available emails to be found. I am missing emails from most of 2018 and 2019. Oddly enough, all my emails from before 2018 are still there, but none of the more recent years. I am trying to find an email thread from this past spring and I can't find any from that time period. Any suggestions? Thanks!