Follow this procedure when switching a customer's email account from POP to IMAP.
Communicate information about mail server type (IMAP or POP3) to customer.
IMAP (think “synced”)
All email messages, including sent messages and message folders, are saved on the server
Email messages may be saved on the computer for offline viewing
All messages and folders can be viewed from any computer or iOS device connecting via IMAP, including Webmail
Most recommended for users who connect to E-mail accounts from many computers
Explain that when you delete an email from one device it is deleted from all devices
Need to be aware of how large the mailbox is because all messages remain on the server. Optonline is now IMAP too but it has a very small mailbox (2GB as of 2017).
POP3 (think “not synced”)
All email messages, along with any attachments, are downloaded to users computer for viewing.
Depending on program configuration, these messages may be automatically deleted from the server once it is received, or at some future time.
Messages sent, moved, or deleted from a computer using POP can only be viewed on that individual computer's folders. They cannot be viewed on other computers connecting to that email account, including Webmail.
POP3 is an old email server type and is not recommended for users, but when moving people off of it to IMAP one must explain what the difference is.
Give examples and be very thorough in your explanation, such as:
If your email account is a POP account, messages read, deleted, or moved, DO NOT mirror the changes to the same account setup on another device.
You can configure a POP email account to keep on server or remove from server, but if you send an email from the server, from a computer, or from an iOS device you will not see these sent messages on the other device unless you have CC’ed or BCC’ed yourself when sending the message. This is why many people when they first got their iOS devices they automatically BCC’ed theirselves on all emails.
If you have an IMAP email account, and it set up as correctly on your devices, whatever you do on one it will replicate on the other, as the messages are stored on the server, and you are making global changes to those messages.
Before Deleting POP Account
CRITICAL: Before you delete the POP email account from the computer, you must backup the email boxes to the "On My Mac" section of the computer.
If you are only making the change on an iOS device explain to the customer that when the email account is removed from the device, all of their email history on the device will be removed. This is important to make aware to the customer, as past sent emails, drafts, etc. will no longer be accessible. If they do not want that to happen do not delete the POP email account, deactivate it instead, and explain to the customer how they can re-enable the account and reference messages, if necessary.
To move POP email to "On My Mac:
In macOS Mail select “Mailbox” from the menubar and choose “New Mailbox…” from the dropdown menu.
Enter a name for the “New Mailbox” (ie: Archive Inbox, Archive Sent Mail, etc.) and make sure you have selected “On My Mac” in the “Location” dropdown menu.
Select and drag all the Inbox mail from the POP email account to the Archive Inbox folder. Select and drag all the Sent mail from from the POP email account to the Archive Sent Mail Folder.
Once you see that the new folders have populated you can then go into macOS Mail “Preferences,” then to “Accounts” and deactivate the POP email account by unchecking the “Enable this account” checkbox.
Setting up IMAP
When you set up the IMAP email the Inbox and Sent box will populate with the emails that exist on the mail server. How you proceed depends on what the customer wants and who the email provider is.
If the email provider is Optonline or some other free email service except Gmail, they most probably have a very small server mailbox (2GB). Please find out how big their mailbox is have before moving into the next section. If they have Optonline or one of these small server boxes you will leave the mail in the archived Inbox/Sent mail boxes located “On My Mac,” and explain to the customer how to see their history.
If the email provider is Gmail or Zmail or a provider where the mailbox is abundant (Gmail defaults at 15gb, Zmail defaults at 25gb) then you can move the archive mail back to the Inbox or Sent mail or you can move the archive folders you created to the Mail server folder. Please understand that this can take a long time if there is a lot of email to transfer. Explain to the customer what their options are and give them instructions on how they can proceed.