On the "ProfileManager" did you tried also other profiles? Isn't there a profile with those old emails & settings?

With the "profile manager" I can select the old profile but with the same outcome. No mails, no folders, no mail accounts.

Just to be sure: there is nothing in the Thunderbird settings (ref those accounts set previous) or you just don't see the "old" and new mails? Is it asking you to add an email (as a first/fresh installation)?

There are no account informations in the settings they are gone. Thunderbird is not asking for a new account configuration. Somehow it is just struggling with the actual profile.

Can you post here your Thunderbird Troubleshooting information? There should be some information ref what's set on that profile: At the top right of the Thunderbird window, click the menu button (or use the regular menu at the top), then select Help: Troubleshooting Information. Click the "Copy text to clipboard" button. Do not check the box "Include account names" Then paste (Ctrl-V), the text into your response here. We only need to see the sections down to and including the "Extensions" section, so you can delete the rest.

here we go:

   Name: Thunderbird
   Version: 78.2.2
   Build-ID: 20200908210243
   Distributions-ID:

   Update-Kanal: release
   User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.2.2
   Betriebssystem: Darwin 19.6.0

 E-Mail- und Newsgruppen-Konten
   account5:
     INCOMING: account5, , (none) Local Folders, plain, passwordCleartext

 Erweiterungen

     Name
     Version
     Aktiviert
     ID

       Amazon.de
       1.1
       true
       amazon@search.mozilla.org

       Bing
       1.0
       true
       bing@search.mozilla.org

       DuckDuckGo
       1.0
       true
       ddg@search.mozilla.org

       Ecosia
       1.0
       true
       ecosia@search.mozilla.org

       Google
       1.0
       true
       google@search.mozilla.org

       LEO Eng-Deu
       1.0
       true
       leo_ende_de@search.mozilla.org

       Wikipedia (de)
       1.0
       true
       wikipedia@search.mozilla.org

       Amazon.com
       1.1
       false
       amazondotcom@search.mozilla.org

       Mail Merge
       7.2.1
       false
       mailmerge@example.net

       Quicktext
       3.2
       false
       {8845E3B3-E8FB-40E2-95E9-EC40294818C4}

.. double post

Name Version Aktiviert ID Amazon.de 1.1 true amazon@search.mozilla.org Bing 1.0 true bing@search.mozilla.org DuckDuckGo 1.0 true ddg@search.mozilla.org Ecosia 1.0 true ecosia@search.mozilla.org Google 1.0 true google@search.mozilla.org LEO Eng-Deu 1.0 true leo_ende_de@search.mozilla.org Wikipedia (de) 1.0 true wikipedia@search.mozilla.org Amazon.com 1.1 false amazondotcom@search.mozilla.org Mail Merge 7.2.1 false mailmerge@example.net Quicktext 3.2 false {8845E3B3-E8FB-40E2-95E9-EC40294818C4}

Yep, sorry :( No account there... Maybe is not all lost - I would try searching for these files: "msgFilterRules.dat" & "Inbox.msf" (or "INBOX.msf") & "filterlog.html". Maybe they were moved something... I don't know how mac works but on win should be searched also on hidden & system files.

Hi together,

after downgrading, putting a backup back in ==> started :) copied back the mail files. And now it seams to work again.

Thanks for the help.