I've located some info, but I've not tried this myself.

http://forums.mozillazine.org/viewtopic.php?f=28&t=2710625 Read comment by morat which start with this line: The folderWidgets.xml file is in the omni.ja file.

Toad-Hall said

I've located some info, but I've not tried this myself. http://forums.mozillazine.org/viewtopic.php?f=28&t=2710625 Read comment by morat which start with this line: The folderWidgets.xml file is in the omni.ja file.

Thank´s a lot - i´ll give it a try!

OK - i looked for all this files, but in the meantime it seems that this files are no longer used - i wasn´t able to find them!?!?!?

The omni.ja file is in Thunderbird program not Thunderbird Profile.

Command Prompt: cd /d C:\Program Files\Mozilla Thunderbird

• This line is for win 32bit - if you use win 64 bit then it would be:

cd /d C:\Program Files (x86)\Mozilla Thunderbird

copy omni.ja omni.ja.17.0.6esr.backup

• This line mentions that particular version 17.0.6esr , but it is likely you are not using that version. You could manually copy the file as a backup to desktop before using the command prompt, so omiting that line.

unzip omni.ja chrome\messenger\content\messenger\folderWidgets.xml

• As it says: the command prompt states it will unzip omni.ja in order to access all other folders.

continue with info at link.

Hi Toad-Hall,

thank´s for your support. I guess in my case it´ll be a little more complicated, because i use Thunderbird 60.3.1 (32-Bit) running under WIN10Pro (64-Bit) and launching the program via "PortableApps.com". That means i found the omni.ja-file under: E:\PortableApps\ThunderbirdPortable\App\Thunderbird, i named it omni.zip, unzipped it, searched for the file folderWidgets.xml, searched for the term _MAXRECENT, changed the value from 15 to 30, saved the file, zipped all together, named it back to omni.ja, copied it over the original one, startet Thunderbird with -purgecaches - but i still have only 15 folders - what went wrong?

after that i tried to simply edit the file omni.ja and changed the valu after _MAXRECENT from 15 to 30, but after that Thunderbird won´t start anymore. After copying the original omni.ja over it Thunderbird works again.

After a lot of tries and checking what gvim is and how it works i made it - thanks a lot to Toad-Hall!!!