I was just reading about what was discovered in the files for No Man's Sky, a lot of things that weren't used or relevant to the game. I also read a short while ago about the E3 settings being left in the Watch Dogs files. Why do game developers leave old and unused files in the final game?

Surely this just takes up extra space on a disc and means more data has to be downloaded if you download the game?

Also, aren't the developers afraid of what people could find?

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    \$\begingroup\$ generally it wont use enough data to warrant deleting it. And sometimes deleting this "unused" Files can actually cause problems to other game objects that use parts of "Unused" files. I think it just comes down to deadlines needing to be met, and the fact that at the last moment content can be cut. \$\endgroup\$
    – Ryan white
    Commented Aug 16, 2016 at 11:55
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    \$\begingroup\$ As a side note, the cutting room floor is full of examples of this. tcrf.net/The_Cutting_Room_Floor \$\endgroup\$
    – drawoc
    Commented Aug 16, 2016 at 17:00
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    \$\begingroup\$ 1) Nobody remembered to delete them. 2) Yes. 3) No. \$\endgroup\$ Commented Aug 17, 2016 at 8:17
  • \$\begingroup\$ An other example is Dota2. Not only the developers leave some asset, they even include incomplete features mean for possible future releases. E.g. new characters, items or skills. So people that disassemble the binary are able to see at least some of the possible future news about the game (notable example: the pit lord/underloard character that was seen in the code years ago has been officially announced some days ago). \$\endgroup\$
    – Bakuriu
    Commented Aug 18, 2016 at 16:23
  • \$\begingroup\$ @drawoc By far my favorite example \$\endgroup\$
    – Izkata
    Commented Aug 18, 2016 at 16:50

6 Answers 6


Major games use something called a build pipeline. This is like another set of tools that handles building the game content for all the different distributions. Multi-platform games like No Man's sky and Watch_Dogs most definitely use different assets for the different platforms. So the way I see it there two possible answers to your question.

  1. The devs forgot to remove certain assets from the pipeline and they got bundled with the actual game.

  2. The devs intentionally left some "unused" assets in the game for later use during a patch or update, because they were unable to meet the deadline. Example Devil's Pit from The Witcher 3.

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    \$\begingroup\$ Also, 3. Deliberately placed "unused assets" so modders/powerusers find them, for sneak peeks onto upcoming releases. Similar to #2, except the content might not even be used in that specific title or future patches. \$\endgroup\$
    – Kroltan
    Commented Aug 16, 2016 at 18:42
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    \$\begingroup\$ +1 for Kroltan's #3. IIRC The Witcher 3 has an example of an easter egg hidden in unused content. There was some secret area that you needed to mod the game to reach that had a photo of the devs or something like that. \$\endgroup\$
    – milk
    Commented Aug 16, 2016 at 21:15
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    \$\begingroup\$ "Forgot to remove" is not a very good way to describe it. The devs may know they have removed their usage of an asset. But its possible another team have started using the asset. In such a case, the possible cost of removal (completely breaking a game) far outweighs the benefit of removing it. \$\endgroup\$
    – Aron
    Commented Aug 17, 2016 at 9:54

It can be harder than you think to find all the referenced content in a large game that is worked on by multiple people. Even when there are explicit tools in place to help (we built such tools at ArenaNet, anybody who uses Unreal has access to Unreal's version of those tools, Bungie has tools that do the same thing and even gave a talk about them, et cetera)

There are several ways content could be referenced that can defeat such systems, generally simply by referencing the content by something that system can't track (such as creating a implicit or hard-coded reference in code to some asset).

Even assuming you have solved the problem of finding all content inter-references, you have the problem of not being able to tell if something is actually used. Maybe some asset is referenced in a script somewhere, but the trigger volume for that script is incorrectly placed inside a wall and the content can thus never spawn in-game. Testing this exhaustively is quite difficult as well.

When automated (or automatable) methods for detecting and filtering out unused content fail, you are left with the old-fashioned way: human intervention. Humans make mistakes, bad assumptions (they may think a file is still used even though it isn't because somebody else made a change), and yes even sometimes choose to intentionally leave irrelevant content in the game as Easter Eggs. It's just natural human fallibility that leads to this.

It's usually not a sufficient amount of content to really move the needle much for load or file size optimizations. There are also tools for reporting the largest or slowest assets in any large build chain or engine, but the focus there is to reduce the impact of the major offenders and not find and locate every single wasted byte. Usually.

  • \$\begingroup\$ Example for an unused file as easter egg on Arqade: Where does 'Song That Might Play When You Fight Sans' appear in Undertale? \$\endgroup\$
    – Philipp
    Commented Aug 16, 2016 at 16:08
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    \$\begingroup\$ Starbounl currently has an issue where you can't get/make "cooked tentacle" because the the bit that teaches you the recipe got deleted. Meanwhile the asset and definition files just sit there looking like they should be working. Considering that over there you frequently learn one recipe for creating/picking up some different item made from the same ingredient (for food anyway), it's easy to see how bits can be excluded from the game just by mistake. \$\endgroup\$
    – Weaver
    Commented Aug 16, 2016 at 17:39
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    \$\begingroup\$ Even if one could find all of the content which is unused by the game which is included on disk, some games are designed to allow users to download extra-cost add-on modules which may be produced by the vendor after the disks have been manufactured. If the disk includes ten megabytes worth of textures that aren't used in the game on disk but will be useful in the download version, that may allow the download size to be reduced by ten megabytes. \$\endgroup\$
    – supercat
    Commented Aug 16, 2016 at 19:16
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    \$\begingroup\$ An old example of where there was a lot of unused assets in the shipped game was MechCommander 2. When Microsoft tested their then new XNA Build tools on it, it revealed that 40% of the game's textures were unused. blogs.msdn.microsoft.com/briankel/2006/01/24/… \$\endgroup\$
    – Ross Ridge
    Commented Aug 16, 2016 at 23:36
  • \$\begingroup\$ Just a note: For Turing-complete languages (and most useful ones are), finding out whether a line of code is ever executed or not is unsolvable (Halting Problem). If you do manage to do this, you might as well ditch the game and collect your Nobel Prize instead. \$\endgroup\$
    – Ordous
    Commented Aug 17, 2016 at 19:36

What's missing in the other answers is that this has nothing to do with games. It affects all applications.

There are always files, and code that isn't going to be used in any reasonably complex program. This happens because of the following 2 things:

  • Programs evolve over time.
  • It's requires effort to figure out if some piece of code or some file is no longer being used.
    • If you remove stuff without spending said effort, the behavior of the application becomes unpredictable

Adding to/ehancing Uri Popov's answer:

  1. Programs may install updates packages that contain new, improved versions of existing asset files and an update to the program itself. For my part, I do not overwrite previous versions of the asset files, because I want to allow a fallback to an earlier program version (imagine, for example, the panic of having distributed a totally disastrous update :-)). The original program version may be using texture_0.dds and the updated one texture_1.dds (hence texture_0.dds is no longer needed). Overwriting (using a single name only) would prohibit a removal of the program update, i.e., the fallback to the original version, unless there was also the tricky mechanics of overwriting newer asset files with older ones. And that is not something anyone wants to support.


Reacting on a comment to the original question,

Nobody remembered to delete them

  1. I would say that nobody dared to delete them. What happens if the game lacks sufficient error trapping (by mistake, ignorance, error, key-person left the company, etc.) at the loading point of that (now missing) file X, and the problem was undiscovered despite intense testing? Say the loading occurs only "every 3rd time", only at level 35 of 36, which you reach only in 4 weeks of intense gaming :-). Lost reputation by crashing software is a brutal phenomen, and it may in the worst case end up in a bankrupt company. Better not touch that file :-).
  • 4
    \$\begingroup\$ +1 for "nobody dared to remove". Not removing an unused asset often only costs a little disk space. Removing an asset that someone else on your team is still using could cost your company a lot of reputation if it leaves big purple checkerboards or causes crashes. \$\endgroup\$
    – Patrick M
    Commented Aug 17, 2016 at 19:55

Why do game developers leave old and unused files in the final game?

Surely this just takes up extra space on a disc and means more data has to be downloaded if you download the game?

Also, aren't the developers afraid of what people could find?

Game developers leave unused files in the final game because they don't want to spend the effort to find and remove all unused files. After all the games runs just fine with a bit of extra material and time is money. Cleaning up increases the costs (depending on how automatized this happens).

While it takes extra space and means more data has to be downloaded, this is usually not the developers problem and even customers usually do not care much about slightly bigger download sizes.

Not sure if developers need to be afraid of anything people might find? Why should they? As long as there is nothing compromising in the extra files (really bad artwork, jokes about their bosses or the customers, ...) they probably do not care much. Although in some cases they are actually afraid of what players might detect in the assets.

  • \$\begingroup\$ Not sure if developers need to be afraid of anything people might find? read the reason why Titanfall 2's tech test isn't coming to PC, they disagree :P. \$\endgroup\$
    – TMH
    Commented Aug 17, 2016 at 8:41
  • \$\begingroup\$ @TomHart You're right. In this case they were afraid. In other cases like the ones mentioned in the question they weren't and included extra assets. I guess that the level of being afraid differs between developers. \$\endgroup\$ Commented Aug 17, 2016 at 9:20

It's been hinted at, but it hasn't been fully touched on by the other answers: it all boils down to cost, and some of the costs are trickier than you might think.

The most obvious cost is that someone has to delete them. Now you could just put an intern on the case and have him go searching through files and whatnot to remove the ones that aren't needed in the actual game. But still, you have to pay for this and, even if you don't (because you're a monster who doesn't pay interns) you still could have had that intern doing something useful like ordering pizza for the dev team, so it still costs you.

The less obvious cost is that the resource you're about to remove was put in for a reason: are you absolutely sure that reason is obsolete? Sure, you wrote this code for a demo and don't need it anymore, but is that entirely true? Did you write a useful function that you forgot to migrate to the other libraries? Did Stacey make a really cool graphic for the demo that ended up in the real game? Does an internal simulator still make use of that old level you used for testing?

Making games is a business. Even if it isn't a money-making business, it's still a business with limited resources. Every decision requires a cost-benefit analysis, even if you don't go writing business cases for each one. And the simple fact is that cost of leaving those assets in the game is a slightly larger download, and the benefits are a significantly reduced risk of something blowing up right before release.

All those question marks in the "less obvious" paragraph represent uncertainty. You just don't know. And when you're running a business, you have to trade your unknowns for knowns. And what is known is that the package you built passed testing, even if it has a little bloat to it.

There other potential costs such as information leaks around the development process that could potentially be used to derive hacks, but you made it through the testing process as-is, you shouldn't really be worried about that.

tl;dr: No one will notice a 4% larger download, but they will notice if you broke the game by removing necessary files.


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