The steps you need to follow to leave POP3 email on the server depends on your version of Outlook.
In Outlook 2010 and newer, the default is to leave all mail on the server for 14 days. This change was made to prevent problems when people set up new accounts and wanted mail left on the server but opened Outlook before setting Outlook to leave mail on the server. Once it's downloaded by POP3, it usually can't be put back. See Restore POP3 Mail to Server for methods.
Outlook 2010 and up users who do not want mail left on the server for 14 days will need to go into More Settings and change it.
To change the settings in Outlook 2010 and newer:
- Click on the File tab
- Click Account Settings button
- Double click on the POP3 account or select it and click Change
- Click More Settings
- Click on the Advanced tab
- Leave a copy of messages on the server settings at the bottom of the dialog.
Only POP3 email can be left on the server or deleted. IMAP, Exchange server, and Outlook.com account types are server-based accounts and mail is always left on the server. If you want to delete the mail from the server with these account types you need to use rules to move your email to a local pst file.
The dialog is identical in all versions of Outlook. If your dialog does not look like the one below, verify your account is a POP3 email account. This option is only available for POP3 accounts.
Go to Outlook 2007's Tools, Account Settings.
With the Account Settings dialog open, the steps are the same as Outlook 2010 and newer: select the account and click Change, then click More Settings. Look on the Advanced tab.
Outlook 2007 More Settings Tutorial
With the exception of the location of Account Settings command, the steps are the same for Outlook 2010 and newer.
Tools, Email Accounts, View or change existing accounts, select the account and click Change. Click the More settings button and look on the Advanced tab.