What account type was the old account? Did you change the existing old account to the new server? Did you create a backup of your profile prior to changing/adding the new account?

I do not understand exactly what do you mean as type of account. It was my e-mail of my web site and I have installed Thunderbird to download all messages from webmail. It was all there then. After having web on new hosting I changed setting in this Thunderbird (to keep it using in my new hosting) and all emails in Thunderbird dissapeared. I do not understand question of "backup of profile". These emails downloaded in Thunderbird was my backup. That is why I have installed. And it was there... And suddenly all is gone. My question is how to get back what was there and is not now. I did noot expect that when I change new smtp or this details, content of Thunderbird in my computer can be lost... Question is if I can find this content somehow in my computer.. Like if I would get back several hours somehow...

I do not understand exactly what do you mean as type of account.

POP or IMAP?

I do not understand question of "backup of profile".

A backup of your Thunderbird profile. http://kb.mozillazine.org/Thunderbird_:_FAQs_:_Backing_Up_and_Restoring

I don't know.. I just downloaded Thuinderbird, wrote my email address and got my emails in. Then, with new hosting I followed settings to continue receiving new emails and old emails FROM THIS DESKTOP THUNDERBIRD application were gone. Also it will not help me to know what could be if I would be making "backup" of this my backup what was this Thunderbird. Reason of posting this my question is - Is there any way, how to get back my messages, which were already in this Thuinderbird IN MY COMPUTER. SOme kind of recovery...

Clicking at link A backup of your Thunderbird profile. http://kb.mozillazine.org/Thunderbird_:_FAQs_:_Backing_Up_and_Restoring

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I don't know.. I just downloaded Thuinderbird, wrote my email address and got my emails in.

That was your first mistake.

Then, with new hosting I followed settings to continue receiving new emails and old emails FROM THIS DESKTOP THUNDERBIRD application were gone.

That was your second mistake.

Also it will not help me to know what could be if I would be making "backup"

Indeed. Not creating a backup was your third mistake.

In a word, you screwed up. And it appears you are not willing to answer simple questions. So consider your messages lost.

This is hard to understand, because as seen all answers show that problem was misunderstood.

I will try to repeat once more what has happened:

- I have not used e-mail client for this e-mail address before, just webmail Then - while moving pages to different hosting, I did not want to lose my e-mails - so - I installed Thunderbird and this way downloaded all emails in and I was happy. (untill here all is fine)

- Then when my web already moved to new hosting - I decided (what I see now was bad luck..) to reconfigure Thunderbird for this new hosting to be able to continue using it (I should not do it I know, would be happy enough if I just keep old valuable emails there). Suddenly my old e-mails lost.

Now - It will not help me to know that if I would do this or that, it would not happen. Here, I search for some idea, maybe some technical detail which is normally unknown, how could I get back to this my valuable e-mails, which I have never deleted or never moved, which were untill this re-setting present in my desktop, in Thuinderbird. Qustion is if there is any help from this present situation, to find these e-mails. Yes - or Not? Many thanks

Can you open help and click on troubleshooting information Then click on copy to clipboard. Paste it in here.

Can you still connect to your webmail? If so are the mails still there?

There is no Help folder there (see screenshot) (Help would be Pomoc in Czech)

If I would be able to connect to old web mail, I would not search for help. Old webmail is gone (now it is empty in new hosting). I can not login back to old webmail.

click on the three bars icon. But skip posting it as you have altered your settings and this will only show your present situation.

In this Troubleshooting information there is a button "show profile" That will open a explorer-window at your profiles location.

Now exit Thunderbird, but keep explorer window open

Under MAIL or IMAPMAIL, if you are lucky, your old accounts-servername will show up. If not, sorry! If it is: Copy the entire account-folder to MAIL\LOCAL FOLDERS

Start Thunderbird If there are any mails saved you should find them in "local folder\your old account"

I'd like to try to explain what has happened, based on my guess that you connected to your original host using IMAP.

IMAP is most likely, since that's what Thunderbird chooses by default, when it is available.

The principle behind IMAP is that you are given a view of messages held on a server. The value of IMAP is that it lets you work with one central message store (on the server) from multiple devices - PC, laptops, phones, tablets. All see exactly the same because they are all looking at the same message store.

So, Thunderbird shows you what's on the server. It makes a local cache of your messages to improve the speed of your browsing, but it would break the principle of IMAP if it made its own static copy of your messages. What you're seeing is a live, frquently updated view of the server contents.

To make a copy of messages on your PC which is independent of the server, you need to put those messgaes in a location which is independent of the server and detached from it. So you needed to make a copy of your old message store, and the mechanism offered by Thunderbird to do this is to store them in the Local Folders speacial account. Many users have fallen foul of this particular arrangement, but I don't know how to make it clearer that Thunderbird isn't automatically offering a permanent download of your IMAP account's messages.

Your second misfortune is another common one; you have, I think, attempted to adjust an existing account to mkae it work with a new server or host. Since, with IMAP, it's showing you a local view of a remote server, all the old messages vanish when you do this. It's always better to make a new account in Thunderbird than to alter an existing one. And it's essential to do this if the two accounts are of differenr types; it is not realistic to convert an account from a POP connection to using IMAP, or vice-versa. Again, it's hard to know how to alert users to the dangers of tweaking an email account's settings in this way. But then again, email hosts and providers don't do a god job of advising their users how to safeguard their messagess when closing an account.

If you are able to follow the advice given in the posts above, you may be able to retrieve Thunderbird's local cache of your IMAP messages.

As an aside, some time ago Thunderbird switched to an alternative Application Menu button, replacing the traditional menus which still appear and are still referred to in much of the existing online help. I would advise all Thunderbird users to enable the old menus (but then I am a reactionary dinosuar who has chosen to spend money on utilities to replace the Microsoft Ribbon with the previous menu system) so to be able to make use of the legacy help on offer. In Windows and Linux, the alt key will temporarily show a menu, from where you can go to View and Toolbars, then select and re-enable the Menu Bar.

@Zenos That was a very good explanation, do you mind if I copy and use that? (with proper recognition of course)

Hello thanks for helps and explanations. But I can not find "show profile" or even alternative in Czech (because I have Czech version) behind three lines menu. It is not there. I found this on my computer C:\Users\oem\AppData\Roaming\Thunderbird\Profiles\pqxnw39s.default\ImapMail but accordng to names of folders it contains only new mails after this my lost.

I was hoping in this help:

click on the three bars icon. But skip posting it as you have altered your settings and this will only show your present situation. (I DO NOT UNDERSTAND - what SKIP POSTING - I need to CLIK AT THREE BARS not post anything)

In this Troubleshooting information there is a button "show profile" THERE IS NO SHOW PROFILE (or Zobrazit profil in Czech) BEHIND OF THREE LINES MENU ... so I cannot continue... That will open a explorer-window at your profiles location.

Now exit Thunderbird, but keep explorer window open

Under MAIL or IMAPMAIL, if you are lucky, your old accounts-servername will show up. If not, sorry! If it is: Copy the entire account-folder to MAIL\LOCAL FOLDERS

Start Thunderbird If there are any mails saved you should find them in "local folder\your old account"

I kind of answered where you would find help (under three bars or ALT+h)

Gnospen said

Can you open help and click on troubleshooting information Then click on copy to clipboard. Paste it in here.

I there asked you to paste it in here. BUT then said to skip posting it (not to paste it in here) as it wouldn't show how you had set up your account before you altered it.

Still in troubleshooting information, there is a button that opens your profile in explorer. It's an easy way to find it.

BUT you have already located it at: C:\Users\oem\AppData\Roaming\Thunderbird\Profiles\pqxnw39s.default So you can proceed:

Gnospen said

Now exit Thunderbird, but keep explorer window open Under MAIL or IMAPMAIL, if you are lucky, your old accounts-servername will show up. If not, sorry! If it is: Copy the entire OLD-account-folder to MAIL\LOCAL FOLDERS Start Thunderbird If there are any mails saved you should find them in "local folder\your old account"

But as Zenos explained the chance is slim but thats what I would do.

Thanks for trying help me... But all folders there are with date after losing the old one...