Please clarify the older emails. are these the ones that were in the old POP inbox? More info always helps. thanks.

David - I have not gotten back to you as I am still checking to see if my older e-mails were even saved in my profile to begin with.

That being said, today my e-mail is really wonky and I do not know if it is some site I opened yesterday or not. My e-mail keeps wanting to download the same e-mails again and again (message at the bottom of the screen) and then some e-mails I saw in my inbox a half hour ago are no longer there but they are not in my spam folder nor trash either.

I ran Malwaybytes with no negative result and my antivirus and firewall seem to be working fine.

By the way, I have been receiving for days a request to compact my e-mails which I have not done - I keep putting it off. Reason being is I recall many years ago agreeing to compact e-mails and in the process I lost a lot of e-mails.

Anti-virus apps might cause those problems in Thunderbird. Two suggestions are often made:

1. As a troubleshooting step, start Windows in safe mode wih networking enabled and see if a problem persists (when the anti-virus software is not running).
2. Create an exception in your anti-virus software for Thunderbird.

Another occasional suggestion is to use only the anti-virus software that comes with Windows, not third-party software.

Rick - this is windows based software and I did not have this happen before now.

Also, I got notice of your message on my cell phone Thunderbird e-mail that is still Pop 3 not IMAP but did not receive your message on my desktop e-mail which I had converted last week to IMAP???????????????

Rick - this is windows based software and I did not have this happen before now. Also, I got notice of your message on my cell phone Thunderbird e-mail that is still Pop 3 not IMAP but did not receive your message on my desktop e-mail which I had converted last week to IMAP???????????????

"Windows-based" is ambiguous. Is it Microsoft's anti-virus software that Microsoft includes with Windows?

POP moves messages from the server to a client. That's what happened on your phone. After the message was moved, it was no longer on the server to be synch'd with the IMAP inbox on your desktop computer. You could set a setting to leave messages on the server even after they have been downloaded to a POP client. Then they would be available to the IMAP client. If you are going to use muliple devices wih IMAP on one of them, you probably want IMAP on all of them.

Figuring out what's happening with your accounts and messages might be easier if we understood what you did to "migrate" "years of Thunderbird e-mails ... from POP to IMAP". What did you do? Deleting and re-installing Thunderbird is not relevant to that change. What else did you do?

David or Rick

I am not going to deal with the profiles anymore. I may have to live with what I was able to transfer to the new IMAP format on my desktop. But now I am getting messages on occasion that will pop up for a short moment saying UID Move failed. Not sure what to do about that.

Would it have anything to do with my phone e-mail being still in Pop3 server mode for those e-mails?

David or Rick I am not going to deal with the profiles anymore. I may have to live with what I was able to transfer to the new IMAP format on my desktop. But now I am getting messages on occasion that will pop up for a short moment saying UID Move failed. Not sure what to do about that. Would it have anything to do with my phone e-mail being still in Pop3 server mode for those e-mails?

If you want to avoid dealing with profiles because of something that I wrote in response to a direct message from you, I was not clear enough. I believe that David can help you get your old messages where you want them and that it may not be time to give up trying.

I am sorry that I do not know anything about that error.

No - I think I only have so much in my profiles - I am not seeing any more e-mails in my original profile I saved. So getting back to the error message and my phone being still on Pop3.....

Fellows - maybe I should revert back to POP3 on my desktop. Just a bit ago, I opened an e-mail on my phone. An hour later I am now at my desktop and that particular e-mail is not even in my Inbox on my desktop. Other from today before and after that e-mail are there but not that one. Not in junk nor trash either. This has never happened before this desktop change to IMAP.

POP moves messages off the server unless you tell the server to keep them. If your POP client gets the message first, it is no longer on the server for your IMAP client.

IMAP is designed to let multiple clients see the same messages. Using IMAP everywhere and POP nowhere makes the most sense to me.

I understand what you are saying but as I mentioned, this has NEVER happened before and is not happening with my other e-mails I first open on my phone before seeing it on my desktop. Just saying......

Anyway, if I convert my incoming e-mails on my phone to IMAP, I suppose then I might lose the prior POP3 e-mails on my phone? Because I have no idea where the profile of those e-mails on my phone would be and where I might save them. Perhaps not the worst thing as I have most of those e-mails still on my desktop.

Create an IMAP account on your phone. If you can identify messages that exist only in the POP account on your phone, copy them to server folders on the IMAP account on your phone. Then they will appear on your computer too.

I am only assuming that such copying is possible. I am not familiar with Thunderbird on Android.

Fellows - I am still have issues with e-mails that appear on both my desktop and android phone. Some e-mails appear on my desktop but I cannot open them. I think I should just go ahead and change my POP 3 incoming server on my phone to IMAP. So I found the server settings section on the android phone. What literally should I input for the incoming server name IMAP  ??? And does the port remain at 110? Note the security type states "None" and which I select it, it does not appear that I can change it from "None". Thanks.

Fellows - I am still have issues with e-mails that appear on both my desktop and android phone. Some e-mails appear on my desktop but I cannot open them. I think I should just go ahead and change my POP 3 incoming server on my phone to IMAP. So I found the server settings section on the android phone. What literally should I input for the incoming server name IMAP  ??? And does the port remain at 110? Note the security type states "None" and which I select it, it does not appear that I can change it from "None". Thanks.

You cannot change one account into another. You must set up a new IMAP account on your phone. Then you can delete the POP account.

OK - so where it states add account, I put in my e-mail address and it states it is already in use. I do not want to change it obviously because I want to sync it with my desktop e-mail of the same name. So doesn't that mean I have to delete the existing Pop3 account first?

And what again am I using for Incoming server name and settings - as shown in my earlier e-mail?

In Thunderbird desktop, I can add IMAP and POP accounts with the same address. I do not know how the Android version works. There is a separate support forum for it.

Yes, you could delete the POP account first as long as you first preserve any messages from it that you want to keep. I do not know if the Android version allows a local account. If it does, you could copy your messages to the local account before deleting the POP account.

Thunderbird desktop usually finds the settings. I do not know if Thunderbird Android does. If not, you can get them from your e-mail service provider or the IMAP account on your desktop computer.

First, you will want to make sure that you want IMAP everywhere. Another approach would be to have POP everyone but leave messages on the server. That would avoid your current problems.

https://support.mozilla.org/en-US/kb/difference-between-imap-and-pop3

https://support.mozilla.org/en-US/kb/faq-changing-imap-pop

https://support.mozilla.org/en-US/kb/switch-pop-imap-account