I never lost my ability to save, however, I did lose one save file that had 213 hours on it. It had my prized Lv. 100 Meganium and Lv. 91 Ho-oh on it. I was trying to get my pokemon to Lv. 100, and it got deleted somehow. But I can still save. I know I didn't delete the save file, and I didn't know anyone who would do that to me, so... yeah.