Almost every time Ive tested the missing auto/quicksave bug, Ive discovered the save is not actually gone and your hours of work were not in vain.

Go to C:\Users\"User Name"\Documents\My Games\FalloutNV\Saves

Here you will see your auto/quick saves and any hard saves. Now if your one of the lucky ones, you should see 2 auto-saves and 2 quick-saves. And THATS RIGHT! One of these is all your hard work. The ones ending in .bak are your correct ones. Simply rename it and delete the .bak. Feel free to delete the other 2 ones that have so frustratingly overwritten your hours of play, giving you a mini-heart attack. After deleting the .bak, you should discover your correct auto/quick saves in the load screen, safely able to continue playing from your original position.

Hope I got to people on time before they auto/quick saved again. Good Luck out there guys!

EDIT: I did put almost btw. About 10% of the time, the file was not actually saved. Sorry bout the guys who lost their work =/
Also, if you auto/quick saved again AFTER originally losing your auto/quick save, you have made a NEW original, and your .bak will be what you just auto/quick saved. So this is a rescue attempt at people who have yet to begin playing all over again, not those who tried again and ultimately wrote over their original progress.

EDIT: the only way to permanently delete your old saves is to permanently play in offline mode. At least till they patch it.
However, this only works with steam-bought digital downloads.
This may also be the reason why the .bak trick isnt working for everyone.
For those it has worked for, could you please state if you were using a steam digital download or a hardcopy?

FIX: With my suggestion, you MUST change the .bak file to .fos once the game is already started up. or you will just overwrite the file you just fixed. So simply alt-tab while the game is already up. I apoligize for this one mistake and hope it helps.

FIX: Now to stop this problem from happening ever again. I, myself use this fix and its perfect. I dont take credit for it. Lady Nibenay was the first I saw post it so I give credit to her.

To those that are still having the save issue just open Notepad, copy the code below (putting your steam uid number in place of [EDITME] which can be found in Steam\userdata) and when you save it, set the type as "All Files" (as opposed to text document) and save it as any filename ending in .bat . Then put that file in the directory where FalloutNV.exe (for me this is C:\Program Files (x86)\Steam\steamapps\common\fallout new vegas). Now, when you double-click this file a small script will run (you'll see a command prompt window open briefly) and the Fallout will start just as if you had clicked the shortcut. Then you can create a desktop shortcut to that file and even change the icon and it will function just like a shortcut. This has completely resolved my problems with auto and quick saves, and you don't even have to turn off steam cloud.

Make the following bat file:

cd ..
cd ..
cd ..
cd userdata
cd [EDITME]
cd 22380
cd remote
del *.fos
del *.ini
cd ..
cd ..
cd ..
cd ..
cd steamapps
cd common
cd fallout new vegas
falloutnv.exe

I suggest the following batch file instead. It is smaller, and more importantly, less prone to deleting invalid files. I know that it is unlikely that *.fos might exist in some random directory, but ini is more than possible.

Here's an easier fix than the batch file. In the ...Steam/userdata.../22380 folder, delete the contents of the /remote folder, then turn off Write Access (for all users and administrators) for the /22380 folder in the Properties/Security tab. That way, no new autosaves or quicksaves get backed up there, and there is nothing for your saves to revert to.

I've been testing this all evening, and it seems to be a reliable solution.

Edit: I haven't lost any manual saves, so I can't say what's happening there. It may be an issue of overwriting manual saves (perhaps that causes a backup to the remote folder), so maybe use new slots and don't overwrite manual saves until they sort this out?

I just denied write permissions to the remote folder.

To those that are still having the save issue, make the .bat file as described on the first page of this thread. Just open Notepad, copy the code from the post below (putting your steam uid number in place of [EDITME]) and when you save it, set the type as "All Files" (as opposed to text document) and save it as any filename ending in .bat . Then put that file in the directory where FalloutNV.exe (for me this is C:\Program Files (x86)\Steam\steamapps\common\fallout new vegas). Now, when you double-click this file a small script will run (you'll see a command prompt window open briefly) and the Fallout will start just as if you had clicked the shortcut. Then you can create a desktop shortcut to that file and even change the icon and it will function just like a shortcut. This has completely resolved my problems with auto and quick saves, and you don't even have to turn off steam cloud.

not only did that not work for me but i cant find and delete that file.. i can save over it still so i know it still exists, but i cant find the damn thing..
though i also tried 2 other methods but i cant seem to remember cause im too frustrated to feel like thinking about it.. one thing i did notice is that every time i did one of those fix methods.. as soon as i start game steam tells me it just updated something for fallout..

so i think im just gonna wait for a patch.. even if that causes me to permanently lose my 8 hours of gameplay, at least ill be able to play it again..
(god i hope the patch will give me back my lastest save.. i had done so much stuff in that 8 hours... like going to every corner of the map discovering [censored] and losing some one of a kind weapons..) really makes me want to use a super sledge on someones face

oh theres a save limit on hardcoe mode? ouch

LOL, no there's not a save limit. The game can only handle tracking 1000 save files at once. Go delete some old saves and the XX/1000 will go down.

So they posted an update today that supposedly fixes the quicksave/autosave issue. It now simply never saves anything to the "remote" folder, so problem solved. I just tested it. Cloud saving is now disabled completely.

A fun side effect of this update is now the changes I made to my ini file to eliminate mouse acceleration in the menus no longer works! How the heck that got changed in an update to fix game saves, I have no idea. The mouse flies all over the place when I move it on the title screen and in the Pip-Boy. I cannot *stand* mouse acceleration. Thankfully it does not occur in the game while looking around with the mouse. If it did, I would be seriously raging. My hate for mouse acceleration is rather extreme. It's bad enough in the menus, but when trying to shoot at enemies it would completely ruin the game. Mouse acceleration is why I only played Dead Space for about 30 minutes before I uninstalled it.

Do not be alarmed. That large thing in the sky is not the ship loaded with ghouls over your town, it's my PC!!!

Got today's patch which was supposed to fix this crap and began to play. I have been in the habit of manually saving since I found out about this bug. When I tried to load the save I did last night, saves 16 thru 21 would not load and the game would crash with the "FalloutNV has stopped working" message. I had to go back to save 15 which is where you have to take the control circuit back to the rocket facility. So i pressed on and got back to where I had been last night. I was just in the irradiated camp in the SW corner Camp S something and died because I wasn't watching my radiation sickness. When my body hit the floor the game crashed with "FalloutNV has stopped working". I tried loading the autosave and the manual save I had done and both would not load and crash the game. I have just deleted the .fos file and modified the write permission on the /22380/remote directory for all group and users. Gonna go back and head into that hell-hole of a rocket facility for the bazillionth friggin time. Thanks for the information. Here's hoping it works for me. Cheers!