So uh I don't know how the fuck this happened but my Metroid Fusion save file somehow managed to get rolled back several weeks.
I've been playing it in VBA-M under Win7. (VBA-M installed in a subdirectory of c:\Program Files (x86); my user account has write access to its directory.)
Anyway, AVG prompted me for a reboot earlier tonight. After the reboot I pulled up VBA-M and found that for some reason there was audio but no video. Tried restarting the program, no change. Loaded a couple other games, no change.
Eventually, after a few restarts/reloads, I opened up Fusion; it displayed a "Loading battery" message. And then when I went to the data screen, it showed a save in Sector 2 with 2 energy tanks. Fuck if I know what happened.
Haven't been able to locate any other Metroid Fusion.sav anywhere on either hard drive. It sure looks like the one I was using somehow managed to get overwritten with an older version of itself.
Complicating matters: my emulators are on a Mac-formatted drive which is mounted using MacDrive. So it's possible MacDrive is to blame. But I don't know what it would have been doing keeping an older version of the file to restore. Especially given that I have a state save in the same folder which is newer (but unfortunately still two weeks old).
Damnedest thing. Obviously the save file had been updated, as I'd repeatedly quit and reopened VBA-M over the past couple weeks and never had any trouble continuing from my last save point until now. So either VBA-M created a separate save file under some name that doesn't contain "Metroid" and it's still floating around somewhere, or some other program (MacDrive, AVG, ...?) kept an old version of the file and restored it, also for reasons unknown.
Anyway, if I don't manage to find my current save, I'm going to say "fuck it" and find something else to play. Because seriously, fuck replaying that much of the game.