You can control whether the Email app on your Android removes messages after they’re picked up. Non-Gmail e-mail that you fetch on your phone typically remains on the e-mail server. That’s because, unlike a computer’s e-mail program, the phone’s Email app doesn’t delete messages after it picks them up.
The advantage is that you can retrieve the same messages later using a computer. The disadvantage is that you can end up retrieving mail you’ve already read and replied to.
Follow these steps:
Open the Email app and visit the inbox.
Touch the Action Overflow icon and choose the Settings command.
On some phones, touch the Menu icon to see the Settings command.
Choose an e-mail account.
Choose the Incoming Settings item.
If you can’t find an Incoming Settings command, you’re dealing with a web-based e-mail account, in which case there is no need to worry about the server delete option.
Below the item Delete Email from Server, choose the option When I Delete from Inbox.
The only other option besides When I Delete from Inbox is Never. If you see the Never option, choose the other one.
Touch the Done button.
After making or confirming this setting, messages you delete in the Email app are also deleted from the mail server. The message won’t be picked up again, not by the phone, another mobile device, or any computer that fetches e-mail from that same account.
Mail you retrieve using a computer’s mail program is deleted from the mail server after it’s picked up. That behavior is normal. Your phone cannot pick up mail from the server if a computer has already deleted it.
Deleting mail on the server isn’t a problem for Gmail. No matter how you access your Gmail account, from your phone or from a computer, the inbox lists the same messages.