I wish my mail would go into both programs at once, though. I guess maybe that's not possible. I can't understand why an Apple Mail tech expert would tell me that it would.
Thunderbird — once you've instructed it to do so — only 'taps into' your other email clients and displays your messages, all of which remain on the original servers. The option does exist to delete the messages from the original servers, but you have to select that option (ie, it's not a default). [FYI, just to be on the safe side (as 'backup'), I leave all messages on the original servers and then every so often I log into the them to delete messages I have no use for.]
Hi:
I'm not quite understanding what you mean by "taps into your other mail clients." I know how to keep it on the server and then remove it. But, I'm not sure what you mean, because when I had Thunderbird up and running, all my mail went into it rather than Thunderbird AND Mail which is what I wanted. Also, in Thunderbird I can barely read the inbox as the letters are so small. I tried downloading the add-on that increase font size but got the message that Safari couldn't open it. Then I downloaded it with Firefox but I don't really like Firefox either. What to do?
I only really want Thunderbird to see if when I get a "gibberish" message in Mail to check and see if it's the Mail program or something else. Honestly, it's not that important. I'm kinda tired of it all.