University of Oregon



What is POP?
POP is short for Post Office Protocol. POP is one method used by e-mail programs to retrieve e-mail from the server. The important feature of POP is that when you retrieve your mail, the messages are moved from the server to the computer you use to check mail.

What is IMAP?
IMAP is short for Internet Message Access Protocol. It is the other main method used by email programs to retrieve mail. Unlike POP, IMAP keeps your messages on the server. When you click to read a message IMAP displays the message that is stored on the server.

What are the advantages and disadvantages of each?

Protocol Advantages Disadvantages

Message storage limited only by the capacity of your computer.

Reading your email from multiple computers or email programs results in messages scattered about.

Messages are stored on your computer. If your computer fails you may lose all your e-mail.


Messages are stored on the server and are not affected if your computer fails.

Easily use multiple computers or e-mail programs to read mail.

Message storage may be limited.

Reading messages while offline requires use of your e-mail program's Offline mode.

Which should I use, POP or IMAP?
Our experience shows that how users interact with their email is intensely personal, and the decision is ultimately yours. However, here are some general guidelines:

  • Use POP or IMAP; do not mix the two. Doing so will cause all sorts of problems.
  • If you use more than one computer or device to read e-mail, use IMAP.
  • If you need to use more than one e-mail program to read your mail, set each program to use IMAP.
  • Do you use Webmail occasionally, in addition to an e-mail program? Use IMAP. (Webmail is an IMAP-only e-mail client.)

If you are still unsure about which to use, or need information on how to switch from POP to IMAP (or IMAP to POP), please contact the Technology Service Desk.