QUOTE(freky @ Apr 11 2011, 05:21 PM)
but i check the Mail setting...it dont have the setting that u mentioned....

I am assuming you are using default mail app
Launch mail app . At Settings/Send & Recieve :
Download option - you can set no of day. Example if you set 2 days, after 2 days, all the downloaded mails before that will be deleted
Further down : Sync deleted items from server - if this is selected , all downloaded mail ill be deleted irrespective when you download it
Further down : Delete mail on server - ON of off. If this is selected yes, when you download mail all your earlier mail will be delted
If you also download mails to your computer - by default the mails will be deleted from server. So if you need to download to your phone - select do not delete from server - check your mail settings on PC or Mac for this. As once mails deleted from server when you use phone to sync all the mails will be deleted from phone . So you have to control it yourself by going to set it on the phone as listed above
This post has been edited by benny888: Apr 11 2011, 05:49 PM