Does the same thing happen in safe/troubleshoot mode (hold Shift when launching TB)? It looks like the Folder Pane, under View/Layout, is hidden.

It's same in safe mode, I've tried it before post. You can see some errors in screeshot. Folder pane is open but can't work regulary it shows empty because of js errors.

I've try install it and some old versions but the same thing continues..

One user managed to temporarily fix this by choosing the Light theme in Tools/Add-ons & Themes:

http://forums.mozillazine.org/viewtopic.php?f=39&t=3111170&sid=40ee9d0ff6a63721cfce18c450028766

Changing theme doesn't work for me.

There are js errors at error panel. I've posted at screenshot. It is about some variable typeerror and about3Pane.js

I really don't have a sure-fire solution for you. Until one is found, I suggest you create a new profile, add your accounts, and see if it works. Afterwards, you can worry about transferring data from the old profile to the new. Help/Troubleshooting, about:profiles, to create and manage profiles; the current profile is unaffected.

An added advantage is that new profiles generally work better with new versions instead of reusing old profiles.

I can't create a new profile because I've 8-10 mail accounts and ten thousands of mails in my profile. I'm using this thunderbird profile since 2008.

I think this is a bug which is about some variable or variable type with theme. Js shows errors. How can I deliver it to developers?

Submit bug reports to Bugzilla for developer attention.

https://bugzilla.mozilla.org/enter_bug.cgi#h=dupes%7CThunderbird

I've controlled all hostname vars at prefs.js. Found and changed one of hostname which has Turkish chars and thunderbird started to works.

The bug seems about Turkish chars or empty hostnames.

Bug report link https://bugzilla.mozilla.org/show_bug.cgi?id=1857824

Thanks all you