POP3 vs. IMAP: Which protocol lets you get all of your email on any device

When some of your email messages appear on one PC, and other messages on another, you're using the wrong one.

red mailbox
Credit: Thinkstock

Wayne Zimmerman’s wife usually reads email on her own PC. But when she tries to read it on her husband’s PC, the messages get mixed up.

I’m going to guess that your wife’s email client software is configured to use the outdated Post Office Protocol 3 (POP3) protocol. POP3 worked fine when most people had one computer and no smartphone. But as people use multiple computers and mobile devices to access their mail, it’s ridiculous.

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When you ask your mail client (such as Outlook) to get your mail, POP3 moves new messages from your mail provider’s server to your client, removing them from the server. If you check your mail on two computers, both using POP3, some messages will only be on one computer, and other messages will only be on the other.

Here are two ways to get around that:

Use a better protocol

Unlike POP3, the Internet Message Access Protocol (IMAP) syncs your client software with the server. All messages remain on both. When you delete a message on your client, IMAP deletes it from your server, as well.

If you want to stick with your current client, you should change your account’s protocol to IMAP. How you do that depends on your program.

In Outlook 2016 (which, annoyingly, still defaults to POP3), you can’t directly change an account’s protocol. But you can create a new account and delete the old one:

1. In Outlook, select File > Account Settings > Account Settings

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2. This brings up the Account Settings dialog box. Click New.

3. In the Add Account wizard, select Manual setup or additional server types near the left-bottom corner.

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4. On next page, select POP or IMAP(Yes, that’s one option.)

5. Fill in appropriate information. Make sure you select IMAP for the account type.

6. Now you’ve got two accounts serving the same email address. Return to the inbox, and drag emails from old account to the new one.

7. Return to the Accounts Setting dialog box, select your older, POP3 account, and click Remove.

Use a web-based client

If you access your mail through a website rather than a program on your computer, downloading messages to one PC or another is a non-issue.

Check with your mail provider. Chances are it provides a web-based mail service.

Or you can use an established web-based mail service such as Gmail. You’ll have to set up a new Gmail account, but you can easily set up Gmail to send and receive messages from  any other mail service (I have four addresses coming into my Gmail account).

1. In Gmail, click the tool icon in the upper-right corner and select Settings.

2. Click the Accounts and Import tab.

3. In the “Send mail as” section, click Add another email address you own, and follow the wizard.

4. Go to the Check mail from other accounts (using POP3) section, click Add a POP3 mail account you own, and follow that wizard.

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Don’t worry about Gmail’s use of POP3. Since everything is going to Gmail, you can access it from any browser, or access Gmail with an IMAP account on a local client.

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