Are the downloaded files for games saved even when the progress is lost after restarting PC?

So I downloaded epic games launcher to play fortnite. I downloaded 50% of the game last night and when I was to resume it this morning, all the progress was lost. So, im asking could the files that were downloaded be in my storage still? If so, where. I’d like to know this because I will uninstall the launcher for good and im wondering whether that 50% is still in my drive.