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What is the difference between POP and IMAP?

Warning: Using POP or IMAP server settings is strongly discouraged. Starting October 2022, Microsoft 365 accounts set up as POP and IMAP won’t be able to connect to their mailboxes in email clients using Basic authentication. Basic authentication is an outdated industry standard that'll be deprecated. We recommend updating your account to use Exchange settings (it might be listed as Office 365 or Microsoft 365, depending on your email client). Learn more from Microsoft.

POP stands for Post Office Protocol, and was designed as a simple way to access a remote email server. The most recent version is POP 3, and is supported by virtually all email clients and servers.

POP works by downloading your emails from your provider's mail server, and then marking them for deletion there. This means you can only ever read those email messages in that email client, and on that computer. You won't be able to access any previously downloaded emails from any other device, with any other email client, or through webmail.

Because POP doesn't sync folders, sent emails are only available in the email client where the message was sent. Emails will not show up on the server or other email clients connected to the mailbox.

IMAP stands for Internet Message Access Protocol, and was designed specifically to eliminate the limitations of POP.

IMAP allows you to access your emails from any client, on any device, and sign in to webmail at any time, until you delete them. You'll always see the same emails, no matter how you access your provider's server.

Since your email is stored on the provider's server and not locally, you may run into email storage limits when using IMAP.

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