I lost my PS2 memory card which had my Star Ocean 3 save file (Right after the mind fuck revelation), and several other games I spent hours playiong. All gone.....

My Pokémon Yellow file... I had invested lots of time into it and then my sister decided to erase the save file. Pissed me off so much that I haven't touched a Pokémon game since then.

I was stupid enough to buy a 3rd party memory card for my Gamecube and had to pay the price. Lost my save files for Skies of Arcadia, Tales of Symphonia, Eternal Darkness, Timesplitters 2, Phantasy Star Online 1 & 2, Crystal Chronicles, Smash Bros. Melee and Wind Waker among others. I had invested a lot of time into these games. Then I played the crappy Star Fox Adventures and that stupid game just didn't like my memory card...

my worst save file loss was the loss of tomb raider 3 save file when i was half way through. so nothing that drastic to be honest. however, if i had lost my dark souls save file when i was at level 94 right before completing it, i would have probably made your 8 year old son look like a very rational highly mature and sophisticated 35 year old adult.

Nothing recent. However, I had a compilation of lost saved files on the SNES back in the day. Holding on to a file of FF 2 and FF3 (US) was simply a nightmare. The files would just vanish by themselves.

Either be when I first discovered that Pokemon Gold etc lost the ability to hold save files, and as a result my file that I'd invested a lot in was gone. Are some of the others I have from that era will be gone by now but I'd rather not know, especially with my original Blue game.

Then a load of completed/nearly completed files from my original Xbox when it Rrod-ed.

Mine was Madden NFL 2004 for the Gamecube. The file size on the franchise mode for that game was huge. When I say huge, I mean huuuuge. It was easily 20 times the size of the files for other games. It didn't even fit on the smaller memory cards. So I had to buy one of the bigger ones.

I actually went with the official Nintendo memory card. The one that was 1000 blocks. The store had third party brands, but I figured I would take the safe route.

I was really into this game. I rarely simulated games, I played all the mini camp workouts to make your players better, I scrutinized every player signing/trade/draft pick. I probably spent more time going through the rosters than actually playing games. The Gamecube didn't track your time like the Wii does, but it had to have been well over 100 hours. Months and months go by as I make my way season by season. I have my best two drafts in a row, so my team is stocked with great young talent on offense. Then seven seasons in...my save gets corrupted.

I was so pissed. I haven't touched the game since. I haven't even bought a Madden game since then.

The funny thing is that my brother also picked up a 1000 block third party memory card at some point. We never had any issues with that one.

My ps3 getting the ylod. Fortunately, I had backed up some of the saves, though most were not up-to-date recent saves. I lost quite a few saves.

Also, my little brother deleted all my saves on my GC memory card. The good thing was I had some of the saves on another memory card.

Nothing too devastating.

Its interesting how many of these stories have to do with hardware failures of some kind and how none of them involve Nintendo.

Long, long, long story short, my gf ended 'accidentally' (as she claims to this day) erased my saved file of Pokémon Red! That totally broke me in so many ways I cannot even express. Four years of hard work with no cheat whatsoever (MissingNo, GameGenie, or GameShark, Action Replay)!
It took her a really long time for her to make it up to me, though, I'm still uncertain if I'll ever be whole again.

Sorry for the necro but I have a pretty good game loss story. First, I will say the most devastating game loss would be my character deleted from PSO on the GCN. I had a 120+ level character (along with some friends characters that were in the 50s or so) and my cousin deleted the game file to start his new character which he played for a total of 5 mins. I wasn't too happy with him and I doubt I will ever let someone young play with my system unchecked again.

Now here is the funny story and main reason why I necroed the thread....

I was loading or saving (can't remember) the save file for Super Mario RPG (on Wii VC) and during the process where it says don't turn off system my iguana walked behind my TV stand and hit the surge protector switch to off. My save file was ruined just (luckily just Super Mario RPG save file) and I had to restart after the game after already completing about half of it. I blew threw the game considering I knew what exactly to do and it only ended up costing me about 2-3 hours loss time (after going quicker the second time).

So my iguana fucked up my save file.