I have been downloading my gmail messages (about 30000 mails & 10GB of data) for the first time on windows live mail and have downloaded about 18000 messages and till yesterday was getting this download status message of having left with approx. 12000 messages.

However today, i opened windows live mail only to find that about 18000 messages remain to be downloaded. 

Why has this happened?

Besides i am getting some mails twice or thrice. How can i help that?

Regards.