Separating multiple audio files saved as one mono file

Using Audacity 2.1.0 on HP with Windows 7 64 bit. I was recording an interview using the Yeti mic connected to PC via USB cable. Four tracks were displayed, only two of them important: the second track was empty, the third just a test. During interview, recording on the fourth track, the screen went black. Then it recovered. In my haste, I tried to save the work, but read I had to export the audio file. So I did to a file I created in my videos folder. I read the warning that all would be saved or rendered as a single mono file but I thought the four would be sequential. Wrong. I am now hesitant to do anything. I have re-read the manual regarding exporting, ( should have exported as multiple tracks but panicked after the crash), regarding importing, about looking at dependencies, and more.
Not sure what to do. The interview file is in the video folder and I can access it (or them because I can hear the two at the same time. I have also imported the file but I have not re-exported it or renamed it, or done anything to it.
Is it possible to separate the tracks, delete the two I do not want, and combine the two I do want?

Why did the screen go black - was it a screensaver?

Unfortunately you can’t unmix the tracks in the exported file.

Did you quit Audacity normally after export? If so it would have asked if you wanted to save changes. If you said yes it would have tried to save an AUP project file. If you have the AUP, try opening that.


Thank you for responding.
I do not know why the screen went dark.
I did try to “save” the files, but the message that came up
stated I could not save the file. I had to export the files.
I did.
I quit Audacity normally; no message came up re saving to an aud. file.
Due to illness, I was not able to work on the audio files I made in May.
I have not imported them yet.

There are 2 choices for import: copy in, which is labeled “preferred,” and go directly to the files and edit them
where they are.

If I read your response correctly, even if I copy in the files, I will not be able to get rid of the overlapping audios?
That means I will have to delete this file/project and start over, correct?

If that happens, try saving to your own Desktop. If you are not logged in as administrator, there are some locations you won’t be allowed to save to, such as Program Files.

Hmm, that is not correct unless you actually had managed to save an AUP (not AUD) project file. I would have a look in case there is an AUP file.

If you only exported one file which was a mix of the four tracks, then as I said, you cannot remove the overlapping audio. Whether you copy in or read directly does not affect that.