I have recently been deleting some old emails from my Thunderbird account in my Windows 10 pc, prior to moving on to a new Windows 11 pc. Suddenly, all my email folders are still there in the left hand column, but when I click on the Folder, which perhaps says there are 400 messages, nothing appears. I have tried the Repair but that hasn't worked. I am an elderly lady (81), and have been using Thunderbird for many, many years, so I have saved emails from a long time ago, that I would hate to lose. I still hear the sound when a message arrives in my Inbox and the number increases by one, but no message? I'm desperately in need of some straightforward advice to solve this problem. The only way I can read new emails now, is on my new computer, or on my iPad.