IMAP help

The short version: I want to download emails to my phone, but not remove them from the server.

The long version: I have Thunderbird on a PC for work email. When it is running it is syncing with the server, so emails are downloaded and removed from the server. This is as it should be.

I use motoemail on my android phone (email app that came with it). If Thunderbird on my PC is running, the phone will not sync with the server as Thunderbird is constantly syncing with the server (this is good). When Thunderbird is down, it will show new emails, but not remove them from the server (this is good). However, when I read an email on my phone it removes it from the server so that I cannot later download it to Thunderbird where I keep my record of all emails.

I cannot find a way to tell my phone to never remove the email from the server. Does anyone know if this can be done, how it is done, and if I need a different email program to it?


You need to specify your device. The Moto Email instructions I can find are device-specific.

Generally the client will have a “leave emails on the server” sort of option.

Note that what you describe is NOT normal IMAP behavior - it’s normal POP behavior.

IMAP generally leaves everything on the Server, so that all clients can sync with it.

It has been a long time since I’ve used a POP client, but I don’t recall this being normal behavior. I recall normal POP behavior being to remove the email from the server upon sync. The OP is seeing the emails removed upon read. Am I misremembering?

I am using a Droid Turbo 2.

This is my understanding of POP. The delete upon read behavior is new to me. Either way, I’m certain how I should go about fixing it.

I have to concur with people saying that IMAP shouldn’t be deleting mail when downloading it. See this article:

Note how you might be able to configure POP3 to leave messages on the server, with IMAP it’s not necessary.

I’m re-reading your OP. You said:

That is how POP3 behaves. Are you 100% sure your email is downloading from IMAP? Because it sounds like it’s not.

The server name is imap02.blah…, so pretty sure.

Server name won’t necessarily tell you anything. What port are you using?


Disregard, I misread.

Damn. When I spoke with tech support they were under the impression of was imap. Of course they were less than helpful. Any way to do what I want with pop3?

Actually, when I enter the login info into the phone it cannot even confirm the server settings so long as Thunderbird is open. When thunderbird closes it works fine. Doesn’t that suggest that Thunderbird is syncing and therefore imap?

I use IMAP on all of my personal mail accounts and I never have that restriction. I don’t think that has anything to do with your download server type.

I’m using Outlook now on my PC instead of Thunderbird but it wasn’t a problem when I used Thunderbird.

This says to me that your server only allows a limited number of simultaneous imap logons and Thunderbird multi-connection is using them all.

Use something like this link to decrease the number of imap connections used by Thunderbird.

Oh, and K9 imap email client for Android is my go-to for an email client - it is imap and it is compliant.

As an example of si_blakely’s original point (server limits number of connections from one IP address): the Courier IMAP server package (which is used a fair bit in many places) has a configuration item which can limit the number of simultaneous connections the server will open to one remote address.

“Ah,” you say, “I’m using two different devices. They can’t have the same IP address!”

If you’re using them on the same LAN, running through a standard wireless router or something similar, both of your devices have the same publically visible IP address (through the magic of IP4 NAT). So, in fact, as far as the IMAP server is concerned, your smartphone and your computer are the same address, and therefore have to share the same limited pool of connections.

An interesting test would be to turn Wi-Fi off on your smartphone, so it’s accessing the mail server through your carrier’s data network. Doing it that way would give it a different publically visible IP address than your PC behind your home router. Then, each device wouldn’t be in conflict over the hypothetical connection limit, and you’d be able to access your IMAP folders from both devices simultaneously.

I suggest this as a test, not a workaround. si_blakely’s advice to make Thunderbird less voracious is the best answer, assuming we have diagnosed the problem correctly.

ETA: And I concur on K9 IMAP email client as well. It’s a good one, and installed on every Android device I have.

Yes, well what Beuwolf said was that generally POP3 clients delete the email once its downloaded by default… It is not a requireemnt of the POP3 protocol.
The POP3 protocol has two relevant commands sent from client to server


The email client can download email one with “RETR 1”, and that does not delete!!!

Only if the client issues "DELE 1 " does the server delete email 1.
So … its totally up to the client, if it doesnt send DELE, POP3 doesnt delete.

Usually there’s an option … “leave email on server” … sub option " For N days"

Checked the other email client I use for the account and it definitely has it set as IMAP.

Downloaded K-9 and it seems to do everything I am looking for. More testing needs to be done though.

Weird problem that I cannot get it to run on my work Wi-Fi network, but when I turn Wi-Fi off it is fine. Might have something to do with multiple devices on the same IP address, but it happens even when the other mail programs are closed. Ah well.

Could it be that when you’re on wifi, your network settings (on the router) have firewall rules that block the needed IMAP ports, whereas when you turn it off, you’re on cellular data and have no firewall?