What were you trying to achieve by installing Thunderbird and set up the Sky Yahoo account in Thunderbird?

What account type did you chose - POP or IMAP?

Did you think about which account type to use prior to setting up the account?

I want an off-line ability to handle emails. Its POP. Thunderbird seems the best/easiest

POP mail accounts can only access and download from the server 'Inbox'. This is not a Thunderbird quirk - it is how all POP mail accounts work.

Thunderbird will then download anything that has not been previously downloaded. As this is a new POP mail account, you can expect to get everything that was in the Inbox.

It is normal for POP mail accounts to download from server and delete the copy off the server. Many servers do this by default as it is considered you are storing emails in your email client. However, you can set up Thunderbird to tell server to leave a copy of the message on the server. Although, you would need to keep an eye on your webmail account to ensure it does not reach it's quota.

Did you set up to keep copies on the server? In Thunderbird 'Menu icon' > ' Options' > 'Account Settings' select 'Server Settings' for the pop mail account.

Is the option 'Leave messages on server' selected or not?

If it was not selected then the emails in Thunderbird may be your only copy. Check this by logging on to your webmail account using a browser.

If you discover that the emails are no longer on server, suggest you create folders in Thunderbird and start working through emails moving them into suitable folders for organising and storage. One method would be to create Message Filters ('Menu icon > 'Message Filters > 'Message Filters) and run them manually on Thunderbird Inbox to move emails to other folders.

Otherwise, one way of ensuring you only download emails say from April this year, would be to logon to webmail account and move older emails out of the Inbox into another folder. If they are not in server Inbox they cannot get downloaded.

I would advise you create a backup once emails are downloaded. Info on creating backups:

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