To provide a safety net against most potential issues (account hacking, no internet access, accidental deletion of messages), we recommend that you download messages to a desktop email client such as Microsoft Outlook or Thunderbird, and keep them separate and intact unless you need to refer to them. POP is ideal as long as you make sure that its settings leave copies on the server so you don’t inadvertently erase the account you’re trying to back up. IMAP is fine too, especially for accessing your emails offline, but as we said, any data erasure disaster that happens, your emails in the cloud will also sync with your desktop client, unless you are careful or tell it to sync manually.
With Gmail, you first need to make sure POP or IMAP is enabled: click on the cog icon (top right), then View all settings and Transfer and POP / IMAP. With Outlook, IMAP is automatically enabled and POP can be enabled by clicking on the gear icon (top right), then Show all Outlook settings and E-mail. Apple’s iCloud emails only support IMAP and are always on, so you don’t have to do anything to set it up.
A modern client like Thunderbird can log in using just your email address and password, although it will use IMAP by default. To opt for POP instead, click Configure manually during the setup process. You can find the different access codes you need online to Gmail and Perspective emails (iCloud only supports IMAP, remember, so Thunderbird can set it up automatically). With accounts protected by two-step authentication, you may need an application-specific password for Thunderbird.
When syncing your emails with Thunderbird, a few checks should be done. If you have opted for POP, right click on the account header and choose Settings then Server settings ensure Leave messages on the server is checked, otherwise your emails will be deleted from the cloud as Thunderbird downloads them, as we mentioned. If you’ve chosen IMAP in the meantime, right-click on the folders you want to be able to access offline, then choose Properties and Synchronization to make sure offline access is enabled.
As we’ve explained before, there are a number of ways to do this, so think about what type of scenarios you want to have contingency plans in place for and how robust you want your backups to be. Individual emails can be downloaded from iCloud on the web, for example, by clicking the cog icon at the top of an open email and choosing Download message. For a handful of posts, that might be all you need.