If this is while you're trying to save something on a Korg keyboard, there are a few possibilities I can think of, but I have no familiarity with Korg models so these are just guesses:
(1) The drive you're trying to save to might be full or have some other problem, such as not being formatted as the keyboard is expecting, or being in a write-protected state.
(2) There might be some sort of problem with the keyboard's save function, such as a bad ROM chip.
(3) There might be something wrong with the data you're trying to save, such as a bad flash memory, which keeps the keyboard from being able to read the data correctly and copy it to the saved memory area.