Hello, I tried to export all tags to a .txt file and wanted to edit tags to export Title and Composer tag, so I edited and saved .mte file but nothing changed, it showed the default Artist - Album - Title etc. format...
Clicked the edit button on mp3tag and opened in Notepad ++, edited, saved and then tried to export tags. When I restart mp3tag app and edit it again, I can see it was changed but the output .txt file is not containing changes.
Could you switch on the messages after an export?
(Ctrl-O > Messages)
That would ask you whether you want to see the result of the export. If you confirm that message, then the text file should be opened.
Produces the expected output on my system: first the title, then the artist and finally the data from the composer.
So I am afraid that you have to investigate further which script you really call and where you save the resulting export.
I cannot see any problem in MP3tag with the information that you supplied.
Even if you solved this by re-installing Mp3tag, usually a solution to the problem you've described would be to edit an export script with the edit button of the Export dialogue Ctrl-E or open the configuration folder with File>Open configuration folder.
This would make sure that one edits the correct script.