You may already know this. I didn't, so I'm putting it here so I can find it again. This is the situation in Windows 10; I don't know about any other system.
Have you ever wanted to change the case of a letter in a Windows file name? Say, "my recipe" to "My Recipe"? It ought to be easy, right? But every time I made the change, Windows reverted back to the original, as if it didn't recognise the change in case as a real change.
The solution—or at least the best and quickest I've found so far—is to make a greater change first, say "my recipe" to "xMy Recipe", and then alter the filename again, taking away the extraneous part, in this case the "x."
It's somewhat annoying, but I've been working intimately with computers since the early 1970's, so "kluge" is my middle name.
