Hi Jay

There's usually 2, one in your Steam downloads folder and one in your Homeworld Remastered folder.

Steam downloads the mod files into its own directory and then the launcher makes a copy into the Homeworld Remastered folder. It's when the launcher is killed during this copy operation that the mod files get corrupted, and the launcher doesn't say it's busy of course...

So ideally you should be deleting the mod big file in the Homeworld Remastered folder to fix a corrupted file issue