IMAP vs POP | Daily Data Support

The Daily Data servers (and most mail servers) offer two ways to read your e-mail, IMAP (Internet Message Access Protocol) and POP (Post Office Protocol). Normally, IMAP is the correct choice for most users (more on when that is not the case later).

What is the difference?

The differences are very basic, and relate to where your e-mail is actually stored by default. Note the by default because there are various ways the following statements can be made incorrect.

IMAP stores your e-mail on the mail server, and POP stores your e-mail on your local computer.

With POP, you download your messages to your local computer/smartphone/tablet, then read them, move them into folders, delete them, etc… By default, the message is removed from the server as soon as some device successfully downloads it. Note that many mail readers allow you to say “leave a copy of the message on the server”, so it is possible to have your e-mail on more than one device, but this runs into problems also.

IMAP, on the other hand, treats your mail reader as a front end to the mail on the server. When you open your e-mail reader, by default the message itself stays on the server and only the header information (who it is from, date sent, subject) are downloaded. Then, when you open the mail for reading, the remainder of the message is downloaded from the mail server. Moving an e-mail into another folder actually moves that message on the server to another folder, and deleting a message deletes it from the server. Again, many mail programs can be set up to download all new messages to your device(s) and keep a copy of them on those devices, but that is not the original intent of IMAP.

Problems with POP

POP fails under two circumstances; when the computer it is running on must be replaced and when more than one device is attempting to access the same account.

Your computer dies

If all of your e-mail is on your computer and it must be replaced, you must somehow recover that e-mail to place it on the new computer. Hopefully you have a backup of your e-mail along with your regular files, but with IMAP, it is not necessary as all you do is set up the account and, since all your e-mail is on the server, it is all available to you there.

The common POP option of “leave a copy of the e-mail on the mail server” is a way around this, but with that, all of your mail is left in the Inbox on the server. If you organize your e-mail into folders, all of that organization is gone; all of your messages will be in your inbox and you must re-organize them. Again, if you are using IMAP, the folders are created on the server, so your organization is there, already. When you open your new mail program, you see what you used to have.

Reading your mail from more than one device

You can use POP to read mail from more than one device (two computers, a computer and a smartphone, or even more). You simply tell both devices to leave a copy of the mail on the server and each one picks up the new mail which comes in.

The problems this creates are 1) you must manually duplicate any organization, 2) deleting a message from one device does not delete it from the other one and 3) all of your mail stays in one folder on the server. The more mail you have in your inbox, the slower the server responds to your request to check mail (think of looking for a new card in a stack of 5, verses looking for a new one in a stack of 5000 and you’ll see what I mean). And, if you add a third device, the same thing happens all over again.

With IMAP, your mail reader simply shows you what is on the server, so if you delete a message, or move it into a different folder, the other device “sees” that also, since it is looking at the server also. And, adding a new device is as simple as configuring the mail reader. Immediately, you see all of your folders and all of your e-mail.

Problems with IMAP

Really, there is only one circumstance where POP is preferred over IMAP; when you do not want your e-mail left on the mail server.

There are several fields where security of e-mail is very critical. If someone cracks the mail server and it has all of your e-mail on it, they can read all of your e-mail.

Under these circumstances, it may be better to use POP and have all e-mail immediately removed from the server as soon as it is downloaded. Then, your e-mail is completely under your control. Some of our clients actually have their own internal mail server and do not want any copies of mail left on ours. For them, we run a program called fetchmail, which checks for new messages every few minutes, downloads them via POP and allows POP to remove them afterwards (default behavior). That way, their sensitive e-mail stays on the remote server only long enough to be grabbed by fetchmail.

However, in those cases, they then set up an IMAP server to store the e-mail, which they then access from their mail readers on their computers.

Converting from POP to IMAP

What if you already have a POP account set up, but you really want to switch to IMAP? It is time consuming, but can be done.

The first task is to deactivate your POP account in all of your mail readers. That depends on which mail reader (Thunderbird, Outlook, etc…) you are using, but there should be a way to disable or delete it.

Now, create the same account but as an IMAP server. If you have had POP leaving your mail on the server, when you do this you will see hundreds or thousands of mail messages in your inbox. These must be moved to someplace for temporary safe keeping. You can create a new folder, maybe named “old” and move all those messages into it (hint, we can do it for you faster, and commercial clients do not even have to pay for the time it takes us to do it).

At this point, you have tons and tons of e-mail, maybe in nice little folders, in your “Local Storage” (ie, on your computer, from the POP account) and one folder with all the old e-mail in it on the server (viewable via IMAP).

Most e-mail clients will allow you to drag a folder from Local Storage to the IMAP account. Doing that will copy or move that folder back to the server, but it takes time, especially if you have a lot of mail. The time it takes depends on your Internet Access Speed, but for any account which has years of messages, it is something that may take hours.

However, the good news is you can take your time doing it. Grab one or more big folders, drag them to the IMAP folder, then go to lunch. It will be done before you know it.

Once you are successful, you can delete the folder “old”, and you can access your mail from multiple devices, knowing that if you buy a new SmartPhone, you simply set up your IMAP account and there are all your messages and folders.

You can also use our webmail to access your mail even when you are not at your own computer.