This is expected results when using IMAP email. IMAP keeps messages on the server and you review them remotely on your devices. Delete a message from any device or at the server and it is gone.

Google IMAP vs POP to learn the difference between the 2 protocols.

Thank you so much for responding, however, I am presently using POP email and the emails remain on the server when deleting from the home computer. The problem is, the messages are downloaded from the server to the android phone and are there until I delete them from the home computer, and the home computer deletes them from the phone, but not the server. I am trying to keep the home computer from deleting messages from the phone? I have turned windows 10 synchronizing off. Would adding a Profile help?

There is no connection at all between your computer using POP and your phone. Nothing you do on your computer will be reflected on your phone.

The only exception to this is that you might have set in Thunderbird to delete the messages from the server after XX number of days. See my screenshot below for this setting.

Thunderbird menu: Tools: Account Settings (If you cannot see the Thunderbird menu, press the Alt key or F10 key on your keyboard to show the menu) Select "Server Settings" under your account on the left side.

The difference between POP and IMAP

With POP, all the e-mails from the server get sent to Thunderbird, Thunderbird saves those e-mails on your computer, then tells the server to delete those mails from the server. Unless you set an option in Thunderbird to not tell the server to delete the e-mails.

With IMAP, the e-mails are kept on the e-mail server. Thunderbird continually communicates with the server to show the e-mails on the server, but doesn't necessarily save them on your computer. You can tell Thunderbird to also save the e-mails on your computer.

When using multiple devices to access the same e-mail, the only way to keep the e-mails synchronized between the devices is to use IMAP.

Another thing to remember, is that anything in the "Local Folders" in Thunderbird are only on your computer.

Most mobile devices use IMAP. When your POP computer downloads the messages and removes them from the server, IMAP devises have nothing to look at.

You could set the computer to leave messages on the server but then it is up to you to manage the server quotas on saved messages.

Hi Bruce and Airmail, I think my problem is solved! I am a 69 year old woman, who has come to computers late in life and am woefully lacking computer knowledge. I did know the difference between IMAP and POP, did have all devices set up on POP, the emails remained on the server, but were deleted from the phone and iPad when deleted from Thunderbird email. Bruce, your picture did the trick. I went into Thunderbird Tools: Account Settings, Server Settings (just as you wrote). I did have to leave message on Server checked, BUT I ALSO HAD "UNTIL I DELETE THEM" checked. I am not sure what difference that made going into Comcast (Comcast kept them on the server), but when I unchecked that 2nd part "Until I Delete Them," everything worked as it should. Thunderbird was only deleting messages on my home computer and not the additional devices. Thank you both so, so much for taking the time to help me. Marlene

It's great that your issue is solved. Could you please mark this forum thread as solved? For the message that provided the solution, click "Mark as Solution".

Please also keep in mind what Airmail said about leaving messages on the server. If none of your devices delete messages from the server (ie are all using POP), then the space available to you on the server will fill up, and then you will not be able to receive new e-mail.

But, I believe that your phone is using IMAP, for the very reason that when Thunderbird did delete an e-mail from the server, that e-mail disappeared from the phone.

IMAP is necessary for gadgets like phones, because they do not have much space to store e-mails, which using POP would do.