Mailprogramm usable under Windows and Linux

[UncleBob]

Hello,

I am looking for a simple program for exclusively e-mail, which runs on both Windows and Linux and whose data I can use on both systems.
Does such a program exist?

Under Windows I used Thunderbird, whose data I unfortunately cannot use in Thunderbird under Linux, the Windows version seems to be newer.
Is it possible to use/transfer the data, i.e. the mails, nevertheless from the Windows Thunderbird in its Linux pedant?

With data I mean the mail accounts including saved mails.

A shared folder or something similar is out of the question, because I keep both systems strictly separated from each other for compelling reasons.

Thanks for your help.

[oshunluvr]

I use Mailspring: https://getmailspring.com/

There's free and Pro (fee) versions. It's not perfect, but works well. I use it on Windows 10 and several Linux distros. I have both work and private emails accounts linked to it. I started uing it because it was the only cross-platform email client that did Gmail and Outlook mail well.

[Fred47]

Why not one of the online programs like Gmail. Can access email on your phone or even Apple.

[TWPonKubuntu]

I use Thunderbird (Ver 68.10.0), but then I don't use anything from Windows, so I don't run into compatibility issues.
Which version of Thunderbird is offered by Windows?

[jglen490]

Hello,

I am looking for a simple program for exclusively e-mail, which runs on both Windows and Linux and whose data I can use on both systems.
Does such a program exist?

Under Windows I used Thunderbird, whose data I unfortunately cannot use in Thunderbird under Linux, the Windows version seems to be newer.
Is it possible to use/transfer the data, i.e. the mails, nevertheless from the Windows Thunderbird in its Linux pedant?

With data I mean the mail accounts including saved mails.

A shared folder or something similar is out of the question, because I keep both systems strictly separated from each other for compelling reasons.

Thanks for your help.

Without using a shared folder, there is no way to be certain that two sets of folders (1 client on Linux, 1 client on Windows) will ever be identical. So that leaves a cloud solution, which is effectively the same as a shared folder; but, while it's yours to use it is not under your ownership. So, unless you have multiple email accounts, webmail works and leaves your emails on one server.

[oshunluvr]

Honestly I'm really confused about everyone's answers and opinions on this. Most of what I read is patently untrue. "Saved" mail isn't saved locally with any service I use. That really doesn't make any sense and as far as I know doesn't happen unless you host the email service yourself. My "saved" gmail messages from 2016 are available on everywhere I access my Gmail - whether it's from a Desktop browser on one on my Windows or Linux machines, when using Mailspring, or on my phone. Google is storing my emails and all the folders and the varied ways I access my account all have exactly the same access. The only exception might be if I downloaded an attachment then deleted the email AND emptied the trash. Then that email would be gone and the attachment would exist in only one place.