A Guide to POP vs. IMAP

About IMAP and POP Email

There are two common email systems in use: IMAP and POP. The basic difference between them is where they store your emails and how folders are synced.

• IMAP stores email on your provider's servers. It provides you reliable off-site storage of your emails. If your email data is important to you, IMAP is the better way to go. If you're dealing with email on multiple devices—say a mobile device and a desktop computer—IMAP automatically keeps everything in sync. Note, however, that once messages are viewed they are stored on your local machine as a cache to improve performance on subsequent loads.
• POP stores emails in folders on your computer or mobile device. While theoretically more private, this also means your email is at greater risk from user accidents, system errors, hard drive failures, computer theft, etc. It also means that every device you use for email may have its own folders and be unable to see or access folders on your other devices.

Postbox can work with IMAP or POP accounts but for the reasons outlined above, we strongly recommend using IMAP for email.

Using Postbox with an IMAP Email Account

Did we say this is how we recommend receiving an email?

Postbox mirrors the emails and email folders on your IMAP provider's server. What you see in Postbox is what's on the server with no action required on your part. Postbox keeps everything updated automatically, checking in with the server every few moments to grab new incoming mail and to update the server with any changes you've made in Postbox. So, for example:

• If you delete an email in Postbox, it'll also be deleted on the server.
• When you create a folder in Postbox, it'll also be created on the server and its contents will be the same in both places. This also applies to renaming or deleting folders. (By subscribing or unsubscribing to a folder, you can show or hide it, respectively, in Postbox without affecting the folder on the server.)

Using Postbox with a POP Email Account

If you're using a POP account, the account's Inbox in Postbox synchronizes automatically with the Inbox on your POP server, checking for new emails every few moments. However, since POP is all about local storage, no other folders you've created on the server, on other devices, or in other apps will be visible or accessible to Postbox. Likewise, any folders you create for the account in Postbox will be visible and accessible only in Postbox.

Note: If you're using POP on multiple devices with a Gmail account, Gmail offers a "recent" mode that can help keep the devices in sync. The details are here.

When Postbox receives new emails from a POP server, it's set by default to leave a copy of the email on the server so you have a backup of it until you delete it from Postbox, and we recommend leaving this setting as it is for safety purposes. The other option is to go to within Postbox to Postbox (macOS)/Tools (Windows) > Preferences/Options > Accounts > your POP account and un-check Leave messages on server. With this setting, however, downloading a new email deletes the copy from the server so that the only remaining copy is stored on your computer, leaving it subject to the usual dangers of a POP account. And should you delete the account from Postbox, the email will be permanently lost. (This means that you should never delete a POP account from Postbox without making sure you've backed it up first.)

How To Back Up POP Email

Postbox offers a few easy ways to securely back up your POP emails into a safer IMAP account. If you don't already have an IMAP account you'd like to use for this:

1. Go to a free email hosting company and create an IMAP account, for example, Gmail.
2. Set up this account in Postbox.
3. Create folders in the account for backing up your POP emails.

Copying Via Contextual Menu

You can use Postbox's Move function to back up emails from a POP account to an IMAP account.

1. Select the POP account.
2. Select emails you want to back up.
3. Right-click one of the selected messages to bring up the contextual menu.
4. Select Copy To and then navigate to the desired location on your IMAP account.
5. Repeat Steps 1-5 for the emails in all of your POP folders.

Drag and Drop

You can also drag and drop emails from your POP account to the IMAP account, however, this will move the messages as opposed to copying them. Here's how:

1. Create an Account Group and drag and drop your POP account and IMAP accounts into the group.
2. Select the group.
   You now have a unified view of both accounts's Inbox, Archive, and Drafts folders. At the bottom of the Folders area is one for each account that contains its other folders.
3. To see an account's other folders, click its disclosure triangle. If you're going to be moving emails between these folders, you'll want to keep both accounts' folders visible for easy access.
4. With the desired POP folder selected, select the emails you want to back up and then drag them to the desired IMAP folder.
5. Repeat Steps 1-4 for the emails in all of your POP folders.