Every time I open a file and then save it as the same name Audacity saves a backup copy…i.e.
If I open 001.wav and save it again as 001.wav Audacity will save the original as 001-old.wav, 001-old1.wav…etc.
I would rather is NOT save old copies.
You asked this question over two years ago. See How do you turn off saving an old copy of a file? - #6 by darkcyber
The answer is the same as then - Edit > Preferences…, then the Import / Export section and set Audacity to “Make a copy of uncompressed audio files before editing (safer)”.
If you set it to read directly from the original then overwrite the original, Audacity makes the “old” copy so that it still has the original data to work with.
Gale
I had this turned off, but Audacity suddenly started making copies again. Haven’t changed any config settings or updated the app since I installed it a few months ago. I’ve checked (safer) and (faster), but am still getting the copies. This is simple converting rips to mp3 with light massaging of the export file. As I say, it was working fine until just a couple days ago, so I don’t know what changed. FWIW, I store my original rips/files on a separate HDD.
Forgot that I installed Audacity on a new machine at my dad’s house today and was working off some files copied to a flash drive and did NOT get the copies. The only thing I did to that install was install the plug-ins to allow me to copy to mp3.
LATER: Well, crap, I just remembered what was happening. Make sure the files you’re trying to save aren’t marked “Read Only”. If they are, it doesn’t matter what your Preferences are set to, you’ll get the extra files. DOH!
Lyle
Gale,
I am glad you can spend your time searching the forum for old posts that people have made and remind them of those. You could have simply answered the question…but I guess it was more important to be smart than to be really helpful. Thanks for your help!
I only “happened” to see your old post when searching for something else, but I did also answer:
Edit > Preferences…, then the Import / Export section and set Audacity to “Make a copy of uncompressed audio files before editing (safer)”.
If you set it to read directly from the original then overwrite the original, Audacity makes the “old” copy so that it still has the original data to work with.
Your old post and its answers contain full explanation of why the old files are retained. Others may want to read that, even if you don’t. 
If “Make a copy” is not working for you, you may have the files set as READ ONLY, as Lyle said.
Gale
I had this same problem, since I wanted to export a file and really have it replace the existing file.
The only solution I could find was to revert back to version 2.0.1.
https://www.videohelp.com/software/Audacity/old-versions
Everything seems to work as expected now.