Are you missing any emails in other folders that you created?

Are you saying that Thunderbird opened showing no emails until it downloaded the ones you received on 25th?

What do you have here: Tools > Account Settings > Server Settings Look bottom right for 'Local directory' put mouse cursor in the text box and use right arrow key to get to the far right, because part of that line will be hidden as the text box is not big enough. Then using mouse left click, hold down and highlight from right to left to get all the line hightlighted. Copy paste the info into this forum. The line should look something like this, but the mail acount name may be different. eg: C:\Users\User Name\AppData\Roaming\Thunderbird\Profiles\yxxxxxxxx.default\Mail\mail.btinternet.com

Then please check Profile folder.

Make hidden files and folders visible.

• http://kb.mozillazine.org/Show_hidden_files_and_folders

In Thunderbird

• Help > Troubleshooting Information.
• click on 'show folder' button
• a window opens showing your Profile folder.

• Click on 'Mail' folder - Assuming you are talking about a POP mail account.

You will see a list of your POP mail accounts, one of them will be 'Local Folders'. OR

• Click on 'ImapMail' folder if you are talking about an IMAP mail account

Please tell me what you see - list all the mail accounts.