ownload emails from your Gmail account by first pointing your browser at google. com/settings/takeout and logging in with the relevant Gmail account (this also works if you’re managing your email using a personal domain hosted on Google servers using its Apps service). Select the data types you want to download (if you just want to download your email, click ‘Select none’ and then click the switch beside Mail. Click Next and select a format and whether you want to be emailed a link to the archive or have it saved to Google Drive. Compiling a mail database can take from several hours to several days, depending on how many messages it contains. You’ll be notified when it’s ready.
Yahoo Mail, Outlook.com and Hotmail users can’t download messages directly this way, but there is a workaround you can perform using OS X’s native Mail application. The trick is to first download the messages in the usual way and then archive them manually. Fire up Mail and pick Add Account from the Mail menu. Select ‘Other’ from the account type options and enter your address and password. Mail will automatically detect the rest of the settings, after which you can allow it to download the complete archive of your mail from the server.
You can now copy the email messages to a secure folder on your Mac by selecting and dragging them out of the message list pane of the Mail app.