When you set up an email account in Outlook, Apple Mail, Thunderbird, or another mail app, you will usually be asked to choose between POP3 and IMAP.
For most people, IMAP is the right choice.
IMAP keeps your mailbox on the mail server and synchronizes it across your devices. Read a message on your phone and it appears as read on your computer. Send an email from your laptop and you can see it later from your phone. Your folders, drafts, sent mail, and message status stay consistent everywhere.
POP3 comes from a very different era. It was designed when people generally had one computer, internet connections were temporary, and downloading mail for offline use made sense. It still works, and there are a few situations where it remains useful, but it is no longer a sensible default for most email users.
Here is how the two protocols differ, why we generally recommend IMAP, and what to know if you are currently using POP3.
How POP3 and IMAP work
Both POP3 and IMAP allow an email program to retrieve messages from a mail server. The important difference is what happens to those messages afterward.
IMAP, or Internet Message Access Protocol, keeps the server as the primary home of your mailbox. Your computer, phone, tablet, and webmail are all accessing the same collection of mail.
If you read a message on one device, it is marked as read everywhere. Create a folder and it appears on your other devices. Move or delete a message and the change is reflected throughout the mailbox.
Your email effectively has one authoritative copy on the server, with each device synchronizing against it.
POP3, or Post Office Protocol version 3, takes a different approach. It was designed primarily to download mail from the server onto a computer. Traditionally, those messages are then removed from the server.
Once that happens, the downloaded copy exists only on that computer.
Folders do not synchronize. Read and unread status does not synchronize. Sent mail remains on whichever device sent it. And if another device checks the mailbox afterward, the messages may no longer be there to download.
That model worked reasonably well when one desktop computer was the centre of someone’s digital life. It becomes much more awkward when the same mailbox is being used from several devices.
Why we recommend IMAP
The most obvious advantage of IMAP is synchronization. Most people now check email from at least a phone and a computer, and often from several devices. IMAP makes that work naturally.
There are also two less obvious advantages that become particularly important when something goes wrong.
Your server-side backups can actually protect your mail
On our hosting plans, email stored on the server is included with the account’s regular server-side backups.
With IMAP, that generally means the mailbox you see in Outlook, your phone, and webmail is also the mailbox being backed up on the server.
POP3 can remove that protection.
If a POP3 client downloads messages and deletes them from the server, those messages are no longer part of the server-side mailbox. Years of correspondence may end up existing only inside one mail program on one computer.
If that computer’s drive fails, the laptop is stolen, or the local mail profile becomes corrupted, the hosting provider cannot restore messages that had already been removed from its servers.
We have seen exactly that situation: a customer assumes their email is backed up because their hosting account is backed up, only to discover that POP3 had been removing the mail from the server for years.
With POP3, the responsibility for backing up those downloaded messages ultimately falls on you.
Webmail can become misleading
Another common support request is some variation of:
“I logged into webmail and most of my old email is gone.”
In many cases, nothing has actually disappeared. A computer configured for POP3 has simply been downloading the messages and deleting them from the mail server.
Webmail only shows what is currently stored on the server. If POP3 has been removing messages after downloading them, webmail may contain little or none of the user’s historical mail even though it still exists locally on a computer somewhere.
Sometimes the POP3 client doing this is on an old machine the user has barely thought about in years.
IMAP avoids the confusion. Webmail, your phone, and your computer are all looking at the same server-side mailbox, so they generally agree about what is there.
When POP3 can still be useful
POP3 is old, but it is not useless. There are still a few situations where using it deliberately can make sense.
You use one computer and specifically want a local archive. If one desktop is the permanent home of your email and you intentionally want messages downloaded and removed from the server, POP3 can still do that perfectly well. You just need a reliable backup of that computer.
You deliberately want to minimize server storage. POP3 can download messages and clear them from the server, keeping the mailbox very small. This used to be a significant advantage when hosting accounts commonly included mailboxes measured in tens or hundreds of megabytes. It matters much less now that storage is typically measured in gigabytes.
Your organization intentionally keeps email off the server. Some businesses have policies requiring messages to be archived elsewhere. POP3 can technically accomplish this, although a dedicated archiving or export system is usually a much better way to implement such a policy.
In other words, POP3 still has uses. They are simply specialized uses rather than the way most people should configure everyday email.
Why “leave a copy on the server” is not the same as IMAP
Many POP3 programs include an option called something like Leave a copy of messages on the server.
It sounds like a convenient compromise. Messages download to your computer, but a copy remains available for your phone or another device.
The problem is that this still is not synchronization.
Your folders do not synchronize. Read and unread status does not synchronize. Sent mail does not synchronize. One device may be configured to delete server copies after seven days while another deletes them after thirty. Messages can accumulate indefinitely on the server, and every device maintains its own independent local mailbox.
The usual result is a confusing mixture of duplicate messages, inconsistent folders, and a server mailbox that eventually fills up.
If you want messages to remain on the server so that several devices can access the same mailbox, you almost certainly want IMAP instead.
The email industry is gradually moving away from POP3
POP3 support is also becoming less important to the major email platforms.
In January 2026, Google discontinued Gmail’s Check mail from other accounts feature, which allowed Gmail’s web interface to retrieve mail from external accounts using POP3. Gmailify was discontinued at the same time.
Anyone who had been using Gmail’s website to collect messages from a domain-based mailbox that way had to move to another arrangement, such as forwarding mail to Gmail or accessing the mailbox with an email application using IMAP.
Microsoft has taken a somewhat different approach.
The new Outlook for Windows, which became Microsoft’s default Outlook experience in April 2026, supports POP3 and IMAP accounts. However, it handles them differently from classic Outlook.
Rather than connecting only between your computer and your mail provider, the new Outlook can synchronize third-party mailbox data through Microsoft’s cloud infrastructure before presenting it inside Outlook.
That distinction can matter for businesses that deliberately chose a particular hosting provider because of where their email is stored.
For example, a Canadian business may choose Canadian-hosted email specifically because it wants its correspondence stored on Canadian infrastructure. Connecting that mailbox through an application that also synchronizes the data through another provider’s cloud changes the data path.
Traditional mail clients such as classic Outlook, Apple Mail, and Thunderbird can connect directly to the hosting provider’s IMAP server instead.
How to switch from POP3 to IMAP
If your mailbox is currently configured using POP3, do not simply delete the account and recreate it.
Some or all of your historical email may exist only inside the existing POP3 profile.
A safer migration looks like this:
- Add the mailbox again as an IMAP account. Keep the existing POP3 account in your email program temporarily and add the same email address as a second account using IMAP. On cPanel-based hosting such as ours, the incoming server is commonly
mail.yourdomain.comusing IMAP over SSL on port 993. POP3 over SSL normally uses port 995, which is also an easy way to check which protocol your existing account is using. - Copy your locally stored email into the IMAP account. Drag the folders or messages from the old POP3 mailbox into the new IMAP mailbox. Your mail program will upload those messages to the server. Once uploaded, they can synchronize to your other devices and become part of the server-side mailbox.
- Verify everything before removing POP3. Log into webmail or check the IMAP account from another device and make sure your important folders and historical messages are present.
- Remove the old POP3 account. Only after confirming that the migration is complete should you remove the old account configuration.
If you are a CanSpace client and are unsure how your mailbox is currently configured, open a support ticket and we can help you check it or walk you through the change.
We continue to support both POP3 and IMAP on our hosting plans. There is nothing inherently wrong with using POP3 when you understand what it does and have a reason for choosing it.
For almost everyone else, however, IMAP is the better option.
The bottom line
Use IMAP unless you have a specific reason not to.
It keeps your mailbox consistent across your devices, ensures webmail reflects what you actually have, and keeps server-side copies of your messages available for the backups provided by your host.
POP3 still works well for a handful of deliberate local-archiving scenarios, but it solves a problem that most email users no longer have.
For everyday email in 2026, IMAP should be the default.
A quick disclosure: we are CanSpace, a Canadian email and web hosting provider, and every plan we offer includes IMAP, POP3, and webmail on Canadian servers with nightly backups.
If you are comparing options, our email hosting plans cover mailbox counts and storage, and our post on webmail vs. email clients is the natural next question after this one. Already a client and stuck on a mail setting? Get in touch and we will sort it out.
