This usually happens if messages from account X are sent through the smtp server that uses account Y's credentials, and account Y replaces X as the sender so that recipients see it as being sent from Y.

Open Tools/Account Settings, select an account in the left pane, then check Outgoing Server (SMTP) in the lower right pane. Is each account sending through an smtp server that is associated with the same incoming account? The situation is the same for identities attached to accounts.

Thank you for the reply. Well, I don't know if the smtp server is associated with the same incoming account. The accounts are independent from each other, but we use the "info" account together. I checked the identity settings for each account, but I didn't see anything weird. By the way we use Google Mail - smtp.gmail.com outgoing server for each account.

And you know, if I create a template, it works well. In the case of my colleague don't. Every account setting looks like the same in the case of my and my colleague's account. Any idea, how can we fix it?

An outgoing gmail smtp server is set up with a specific username (address, if you will) and as described, will swap its own address in to replace whatever address you think you were using. The solution is to set up a separate smtp server for each incoming gmail account, each using the corresponding username (address) and password. You also need to label these clearly, via their "description" field, so you know which is which.

What mechanism are you using to be able to share a templates folder?

If you can't or don't wish to set up separate smtp servers for each .hu account, as mentioned above, and continue using the gmail smtp server for all accounts, another option is to add the accounts to the gmail account, on the gmail website Settings (Accounts & Import). That way, messages can be sent from non-gmail accounts through the gmail smtp as before, but the sending address is not replaced by the gmail address. This can be useful if, e.g., the separate smtp servers don't use secure connections, rendering them unusable when you're sending on a different network, such as with a mobile device.

Hi All! Until now, I couldn't solve the problem, so I will uninstall and reinstall the Thunderbird. Before the uninstall, I want to export all of the personal settings/datas. For eg. contacts, events, signature, but I don't know how to export the added words from the dictionary. (You know, when you use a word and the Thunderbird doesn't know it, you can "add to the dictionary". Does anyone know how to export these words and then import them?

The profile folder file with the added words is persdict.dat.

But I don't think this problem, as with most problems, will be fixed by reinstalling TB, a process that doesn't affect the profile folder, where all user data are stored. It's still not certain how your smtp servers are assigned to individual accounts, or where the Templates folder(s) is defined.

If you think it's necessary to 'start fresh' but retain the current data, I suggest you create a new profile with Profile Manager and copy calendars, contacts, persdict etc. from the old profile to the new one. To start Profile Manager, press Winkey+R and type

thunderbird.exe -p

http://kb.mozillazine.org/Profile_manager

http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Thunderbird