It does not matter what I set as the Macro output directory in the Edit->Preferences->Directories, the MP3 export file is not created there, but in the c:\users\defaultuser\Documents\Audacity\macro-output folder. If it didn’t exist, Audacity will create it.
A very interesting phenomenon, because It worked approx. for 10 exports, not once after that. Reset Configuration has also no effect.
Is this a general service computer? One that has a bunch of different jobs?
What were the jobs after the last good export—even though it would seem to have nothing to do with this problem? Skype, Zoom, Meetings, and other programs change computer configurations when they run, for one notable example.
It is also possible that you have more than one version of Audacity installed on your machine, and that you have somehow invoked the older version.
To eliminate this as a possibility, uninstall all versions of Audacity. You can also spot-check both C:\Program Files and C:\Program Files (x86) for an “Audacity” subdirectory. Then re-download and install from here: https://www.audacityteam.org/download/
If the project has been Saved, then the exported files will be saved in a folder named “macro-output”. The “macro-output” folder will be in the location specified in Directories Preferences.
If the audio in the project came from an imported file as its initial step (that is, it is a named project), the “macro-output” folder will also be in the location specified in Directories Preferences.
If you set a default folder for Macro output Audacity will create a folder called “macro-output” in that folder and that will be used for exports from Macros.
I am working with e-books. Every time I finished a part of a book, I have to go to the macro-output folder, and copy back the exported mp3 file to the project directory.
It is really annoying. I think a parameter is exactly what it is - nomen est omen - to do whatever I want with it. If I want to put the macro output in a specific folder, then let me put it where I want it. Seriously. I really wonder, what is the purpose of this (or any) configuration parameter if it can’t take any value I set.
Bugs also need to be reported on the same GitHub issues log.
But I’m unsure that what you have is a bug - it works for me on W10 - I did a lot of QA testing on this when ex-developer James Crook improved the Directories preferences adding a lot more options.