- For a webbased ONLY mail, you've got to trust the provider that he does a backup. That's the same as for all SaaS-providers.
- For any pop3-based email the mail is copied to your PC and can be backed up like any file on your PC. In this case it's your responsibily.
- Then there are the services (like gmail and yahoo plus) that offer both. They are primarily webbased, but have a pop3-interface also. People can then have 3 copies:
a. The original with gmail or yahoo.
b. On their own PC.
c. On the backup of their own PC.
That should be rather safe.
Kees
Is there one email provider, outlook, thunderbird, yahoo, google etc that has a backup routine to allow emails to be backup, thus not lost, so far I cannot find one. Backing up email, preferable off computer, should be part of every emails providers software so in the event of problems, inportant emails are not lost

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