Please give more information, such as whether this is a POP or IMAP account. If a POP account, and if account was set to delete from server after download, then they are probably lost. If an IMAP account, then nothing is lost and you would just need to reestablish the account. You can verify what files are still available by logging on to your email provider's website account. Of course, if you made a backup, we can help in recovering it. Thank you.

Spectrum is my email provider and they delete emails after they are sent to my Thunderbird account. There are no emails at Spectrum. Once in TB I either delete or place the emails in various folders where they remain forever. I have no idea if I am POP or IMAP. I had presumed that the folders I set up and the emails I placed in those folders remained somewhere backed up in the TB "Cloud." I'm beginning to get the feeling there is no "cloud." I just tried this: https://support.mozilla.org/en-US/kb/profiles-where-thunderbird-stores-user-data?redirectslug=profiles-tb&redirectlocale=en-US#w_how-do-i-find-my-profile But I can't seem to make this work. I did not make a backup of my TB email account. I'm beginning to think emails are like phone calls. Once you hang up those conversations are gone forever.

> I had to replace my hard drive

If no backup, and account was not imap then you are out of luck, because pop accounts only have the messages on your local PC by default. As you say "Once you hang up those conversations are gone forever."

But Spectrum do support imap https://www.spectrum.net/support/internet/spectrum-email-server-settings