Sorry for the SUPER late reply. What should I do. A couple months ago I swapped the battery and the saves just fine and then I got the message like a couple weeks later. Change for a new battery and it’s the same result weeks later. I assumed it was because I abused the controlled Pokemon encounter glitch aka “Mew” glitch but I tested playing the game from scratch until I got to Pewter City, saved, turn off, wait 5 seconds, turn on and the thing says the file was destroyed. I run an emulator on the pc with the file I shared with you but like you said it runs just fine. What is wrong with the cart? I got this new as a kid back in like ‘98. After a while the battery died and when I turn it on it just asks for a new game. That’s all. No destroyed save at all.