Which OS/version are you running the game on?
In which folder did you install it?

Some folders like Program Files / Program Files (x86) are especially protected and you may need to run the game as administrator to make sure it's allowed to write the save files in there.

I am using windows 10.
I tried to install the game on a dedicated folder on the D drive and on the default directory : it's all the same.
Administrator mode or not.

If it was an administrator issue it would fail all the time. But it is not. Sometimes it works and I can reload my saved game.
And sometimes there is no saved game to load.
But I never managed to play more than half an hour without hanging.

You might want to try DevilutionX, it uses atomic caves so even if there is a write error your previous save game isn't lost, also it doesn't have the issue with requiring admin rights or most of the other compatibility issues.
https://github.com/diasurgical/devilutionX/releases

Make sure you Save your game. And only use the Load Game menu option.

The only time it is ok to click "New Game" is if: Your character is alive AND you are in-game AND your game has been saved. If these conditions are met then "New Game" will simply send you back to the main game menu.

However if you have not saved your game OR you are dead OR you are at the main game menu, then clicking "New Game" can result in you starting over at level 1 with a new character.

This may or may not be the cause of your problems but it is very important to understand this as a new player starting a single player game.


Can you provide more details of the exact moment you "loose your character"? What is happening before and after this moment?

Can you provide more details about what the "game hangs" means. Explain in detail what happens before, during, and after these moments.

Your topic title says you lose your save files. How are you verifying that safe files have been lost?

The cause of the problem is definitely that this game (the GOG version I mean) is shit.

The save/load function in the game works (I played this game at the time an all the next versions since. I know what saving a game or creating a new one means, thank you very much). So most of the time after a crash I can reload my game. Most of the time only. Once in a while when I want to reload the game, my character list is empty and the only option is "New Game".

The game hangs : when I quit a level (take the stairs or a town portal) sometimes the game just disappears leaving an error message box indicating "Unable to open save file" (the guy who coded this message doesn't even speak english properly).
This is the cause of the problem.

Is the amount of free space on your drive close to a multiple of 4GB?
The game checks to make sure there's room before writing the savefiles but can't correctly handle the amount of free space possible on today's HDDs, so the value wraps around... so if you had 4.001GB of space the game might see it as 0.001GB.

(iirc the rollover value is much higher than 4GB, I just picked it for the explanation).

That's terrible. I am not aware of anyone else having the issues you're having, though... so I wonder if it's unique to something in your own setup?

The game saves have to be made MANUALLY... the game doesn't auto-save (in singleplayer or LAN... if you're playing Battle.net, I think it does, though, online... right?)

Your save files should be unique files, right in your game directory. For example, for ME, mine is here:

"F:\GoG\GalaxyClient\Games\Diablo\dx\single_0.sv"

I hate to give the "routine auto-reponse" comments... but (1) are you sure you don't have an issue with your hard drive health, (2) is your OS running well (do you have issues with other programs, (3) have you tried uninstalling and reinstalling, (4) have you completely restarting your system, after doing a full system cleanup?

This sounds more like general system instability than it does like an issue with the game. And if your save files are being DELETED... well, that's more likely an indicator of a failing hard disk than anything else. Why don't you start a game, save your progress, and see if the save game file is there?

Oh, and not meaning to talk down to you... is there free space on the drive? Is it encrypted, or compressed, in any way? And so on and so on. Since the game doesn't "auto-save," it should create an intact save game file anytime you choose to save... and if the disk is working, this file should NOT be "deleted"... ever... unless you specifically choose to do so. If files which are not being accessed are randomly disappearing from your drives... you have bigger issues.

All forms of multiplayer (LAN, serial, modem, and battle.net) followed the same rule: automated saving of the character (but not the dungeon) on a schedule set by the game. Saves are written to local storage, not to battle.net. For Diablo v1.09, character saves are named multi_N.sv for numeric N, in the same directory as single player saves. I don't know the exact rules for when it saved, but I know I've seen it save while playing, because of cases where someone crashed out of a game (without choosing New Game or Quit, just the program died or the computer lost power) and their character state reflected at least some of what had happened in the game (e.g. items they dropped in town did not reappear in inventory because the game had saved that the item had been dropped).

A multiple of 4GB ?
Are you seriously writing this ?
There is 240GB available on the drive. Should I make it 239.9 to save the problem :) ?
-> non sense. Common developper answer indeed (I should know, that's what I do for a leaving :)).
The problem cannot come from your code. It has the come from the users configuration.

Well, it does not.
My configuration is OK. Everything is running fine on my computer thank you.
The hard drives are almost new and show no sign of weakness.
But thanks to take some time trying to explain that if your stuff is not working it must be my fault :)

Considering how rude you seem to be, your characters are probably erasing themselves out of existence to get away from you.

P.S. "Unable to open save file" is perfectly valid English. Maybe it's your comprehension that is poor.

Yes. I don't know if it's right, but it's a fairly reasonable explanation. If the game is truncating free space by discarding high bits from the counter, then yes, (2**32) + 1 $units would be misrepresented as 1 $units. As a developer, I would expect you would notice magic numbers like 2**32. ;) squid_80 also said that the rollover is higher, so it's probably truncating to a 32-bit number counting some larger unit, like 512-byte sectors, rather than counting bytes individually. The principle remains the same though.
You could try it. It wouldn't take long, and if you're this certain the advice is incorrect, wouldn't you like to prove it?
I doubt that anyone answering you has any involvement in developing the affected code. We were offering you some free advice that is at least rooted in reasonable guesses, if not personal experiences. Also, no one ever said the existing code is good, only that it has a known issue with certain user configurations and that, if you know the issue, you can configure around the bug. If you don't want to take this advice, you're welcome to go back to crashing. I've never seen this particular problem with Diablo, but I don't know that I ever had free space at a special level.

Uh... kiddo... at what point did you somehow conclude that "I'm the writer of the software?"

FYI, I'm not. I was actually trying to HELP YOU. And you don't seem nearly as informed on these matters as you seem to want to pretend, as the first step in solving ANY problem is to examine what's actually happening, and ensure that there is no more "mundane" issue at work.

I'm merely a fellow end-user. And one who went above and beyond in the hopes that I might help you a little bit. But you seem incapable of grasping such a simple concept. Oh, NOOOOO... you're the "victim" of some horrible "conspiracy" (despite, as far as I've seen, ZERO other end-users having the issues you are having).

Am I wrong about that? Can you point out where other end-users have experienced "having their saved games deleted?" I haven't seen a single one prior to you, or since you for that matter.

If you are the ONLY one, out of tens of thousands (minimum) of purchasers... well... it seems unlikely that it's an issue with the code, doesn't it? I mean, if it were really a CODE issue, shouldn't virtually every single end-user be having the exact same issue with "saved games being deleted?"

C'mon, if you REALLY "do this for a living," surely you can do the most simplistic of "root cause analysis," can't you?

Nah... seems like you're B.S.ing here. And pissing off those few people who care enough to actually try to help you.

So... consider yourself ignored from this point on, kiddo.
Hear, Hear!

By the way, our pal here has one GoG game, with a total of three hours (meaning somewhere between two and three) total played, and the only posts ever made are in this thread. Which may mean nothing, but certainly draws into question his bona-fides about being an "expert" on any level. He bought this game, has barely tried playing it, and now is complaining that "it sucks" and insulting anyone who attempts to help him.

So, best to ignore him entirely from this point on.

Well, the root cause analysis has been made : the game is crashing on a basic functionnality of the game (taking the stairs). The root cause id that there is a bug in the code :)

You might think you're helping. You are not.
I just came with a bug in the game and you tried to explain to me that I had a major hard drive failure...
And I never insulted you.
Pointing out that you're telling nonsense is no an insult, is ist ?
Multiples of 4GB, seriously? And you dare write you're helping ?

I barely tried to play it?
Well the game is crashing 80% of the time when I try to enter or leave a zone.
Now, I am stuck at the 3rd level of the cathedral.
My inventory is full, when I try to take the stairs up the game is crashing.
When I try to take a town portal the game is crashing.
I seriously doubt I will reach the hundreds of hours of play in these conditions...
Though I spent them on the game 20 years ago.

Well it doesn't matter.
If any one has got an idea about this bug or if by luck a dev is reading (there is not support on the game) you're very much welcome.

On the other hand if you you want to "help" telling such things as "you are not admin of your computer","your hard drive is highly deficient" or "to save a game, you need to use the save option in teh game", you may just remain silent.
Thanks.

That literally nobody else on these forums has even mentioned experiencing. That alone makes this suspect.

Go raise a ticket with GOG Support.