I have just found some serious errors/corruption in my TB profile. I'm moving my email to Google's servers from my existing POP setup. So, I was going through the process of moving my email from my local TB client to Google's IMAP server. It was during this process that I realized something was wrong with my Sent Items folder. It would only copy email from September 3rd on. No matter what I tried or where I tried to copy the emails to, only those emails would copy. I then tried Repair Folder on the Sent Items folder and ALL of the emails prior to September 3 vanished!!!! I checked my backup of my profile and it also had the same corruption, so that was no good. I had recently moved to a new PC on August 29th. So, luckily, I hadn't formatted that PC yet and so I was able to grab the Sent Items from that machine and copy it over. I noticed that the file on my current PC (the file with no extension that accompanies the msf file and mozmsgs folder) was right around 90MB, while the file from my old PC was 1.8GB. So, there is definitely some major data loss on my new install. Copying that over got me all the email up to Aug 29th and then I copied over the emails from September 3rd now from what I had copied to the GMail server. I'm still missing any email between August 29th and September 3rd, though. I figured I could live with that and began copying the older emails to the GMail server. That's when I noticed that a lot of the older emails (from early 2015 and back) were missing email address information. In TB, it just shows "Name <>" for the From and To fields. I opened up TB on my old PC and the email information is there. So, it gets lost in the copy from that machine to this one somehow. At this point I am stressed out. I am almost too scared to look to see how much other email is lost in other folders. This is a really big problem and it has really shaken my faith in using Thunderbird at all. I can't just have emails starting to disappear for no apparent reason. I've used the migration methods to move TB from one PC to another. I don't know when or why this is happening. Any help that can be provided is very much appreciated. Thanks, Matt Tyree