Archiving emails locally outside of Apple Mail/Server I'm migrating from two very old (the oldest from 2004) Gmail accounts to one iCloud Mail. Unfortunately both accounts have, together, around 30k uncategorised emails in their inbox, from which probably at least 70% could be deleted.
My goal is to have those email accounts completely empty and clean, and check them every once in a while in case something important (old acquaintance, etc.) pops up, or in case I use a service linked to that account (which I would change to my new email).
I gave up the idea of going through all 30k emails and picking up things that I might want to keep. I don't want to get rid of old emails of friends, family and other loved ones, so I'm looking for a solution to download the emails to my MacBook Pro (probably directly from Apple Mail) and store them in the hard disk in case I ever need to look for anything that might be of interest from the past, just feel nostalgic and want to go through old emails, or I happen to have the time and energy in the future to sort the emails out.
Is there any method you would recommend to export all emails and attachments and store them in a way that I can easily browse or search for keywords?
Thank you
You can add both Gmail accounts, wait for complete sync, and then

export each mailbox to your Desktop (or wherever you may want to on
your computer).
import the whole folder containing all the desired mailboxes to your Mail app.

You can then delete the synced accounts contents either on the Mail app or on the Gmail interface.
You'll end with a local backup of your accounts contents and two empty Gmail accounts synced to your Mail app.
You can skip step 2 if you DON'T want to have the contents of your old accounts available on your Mail app at the moment, and import them later on when you see fit. I'm afraid you won't be able to browse the contents of your backup (text or attachments) without first adding the whole mailbox to your Mail app.
You can also remove the old Gmail accounts from your Mail app if they start getting cluttered with spam (although you can teach Gmail what is spam by marking it as such on the Mail app interface or by dragging spam to the &quot;Junk&quot; folder.