Most POP mail clients will automatically remove the messages from the mail server when it downloads them unless it is specifically configured to leave mail on the server. All of your emails should be saved locally on the computer that your POP client is on and still available from your mail client on that machine.
If you wish to leave a copy of the mail on the server so it can be accessed from multiple locations, you will need to change your download settings:
- For Outlook, click on Tools > E-mail Accounts select "View or change existing e-mail accounts" and press "Next". Select the correct account and click "Change", then the "More Settings" button. You will then go to the "Advanced" tab and find the "Delivery" section at the bottom. Check "Leave a copy of messages on server".
If you want to put your mail back on the server, you will need to reconfigure your mail client to connect with IMAP instead of POP and then import your mail back to the server. You will need to find the file that your mail is being stored in and then import the data in your IMAP mail profile, or simply drag and drop the mail from your local folders into the IMAP inbox.
Note: After you import mail via IMAP, if you connect with the POP client again, all of the email will download a second time and show up in your POP mail client as duplicates. In order to avoid duplicates, it is recommended that you move the mail from your inbox to another local folder before you connect back to the mail server via POP.