Unwanted File Content Swap
After I had completely composed my new compositon I open it up in my folder again because of confusion from my backup file in my folder. That somehow causes an older file to be loaded under my current composition name and my current composition is now (as far as I know) gone forever.
Comments
If you've saved the last changes of your completed score, it should be somewhere. If you don't remember on the directory, use the search engine of your system, search for all "mscz" files, sort it maybe by date, it should be somewhere in the search result.
In reply to If you've saved the last… by kuwitt
doesn't work
In reply to doesn't work by ahetu
Search for all .mscz, files looking a invisible files as well. See https://musescore.org/en/handbook/recovered-files and https://musescore.org/en/node/52116
As mentioned, if you are positive that you saved it, then it absolutely positively has to be there somewhere. It's just a matter of figuring where you actually saved. Due to the aforementioned confusion, could well be you accidentally saved it with a different name or in a different fodler. If you are positive you saved it, then have the confidence to keep looking, and you will find it.