Using save states alone is the worst idea in most emulators just because if the game crashes at a later stage you can't change setting to fix any issues as save states also save emulator settings and as you have just found out they can become corrupt easy, even if you only save state at static screens like menu's or pause screens
There is no come back from a corrupt save state though, you either need to load an older save state or a memory card save or re-start the game if you don't have either of those
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