Wat?
Could someone assplain to me?
Save file protection? Please explain.
From what I gathered earlier in the thread:
Every time you save your game it generates a new, random "Save ID" and stores that ID in both the SD/Savgame and the 3DS's system memory. Trying to load a save with mismatched IDs will result in being forced to wipe the save.
This prevents two things:
1) Having two towns with one copy of the game by using two SD cards.
2) Reverting to an older backed up save to undo changes you aren't happy with.
Unfortunately, there's a third, collateral damage situation.
3) You back up your SD card, play AC, your SD card dies. You now cannot restore from your backup because the IDs don't match anymore. Your town is gone forever.