Hi. I have following problem: I am in short of hard drive space and I have discovered that my Unreal Engine instalation occupies 54GB of 100gb total system drive space! There is only 2gb of free space left! That’s ridicolous because inside Unreal Projects folder ( inside my documents ) I have only two copies of my project ( 10 gb each ) , but there is also some folder in AppData, which occupies 32GB ! I need this space. Is there any way to free it ?
Thank you.
Do you probably have several engine versions installed? -> e.g I have 3 version with 32GB 
I assume that the Epic Devs work in a Networked environment with massive amounts of storage and are unaware of the constraints that apply to most users.
so thats where my space is dissapearing to
…AppData\Local\UnrealEngine\Common\DerivedDataCache
this folder grows by about 1gb every day it seems
what is it and can we delete it?
You can delete the huge cache files I think, the catch is UE4 will rebuild a lot of data next time you use those files.
Never noticed that before. Apparently all the data for uninstalled previous versions since 4.0 is stored there too(separate folder for each engine version…)17GB. :\
I as well would like to know if it is safe to delete them.
You can move the DerivedDataCache stuff into a different folder with some config modifications in your projects DefaultEngine.ini
The Folder itself is safe to delete. But then the editor will have to recompile every material.
[InstalledDerivedDataBackendGraph]
MinimumDaysToKeepFile=7
Root=(Type=KeyLength, Length=120, Inner=AsyncPut)
AsyncPut=(Type=AsyncPut, Inner=Hierarchy)
Hierarchy=(Type=Hierarchical, Inner=Boot, Inner=Pak, Inner=EnginePak, Inner=Local)
Boot=(Type=Boot, Filename="%GAMEDIR%DerivedDataCache/Boot.ddc", MaxCacheSize=512)
Local=(Type=FileSystem, ReadOnly=false, Clean=false, Flush=false, PurgeTransient=true, DeleteUnused=true, UnusedFileAge=34, FoldersToClean=-1, Path="%GAMEDIR%DerivedDataCache")
Pak=(Type=ReadPak, Filename="%GAMEDIR%DerivedDataCache/DDC.ddp")
EnginePak=(Type=ReadPak, Filename=../../../Engine/DerivedDataCache/DDC.ddp)
this should put the stuff in your project’s DerivedDataCache folder instead of the one in AppData/Local/UnrealEngine. For the projects folder location I never had problems with that, because I configured Windows so that the Documents-folder is not located on another drive, but I think the UnrealProjects Folder can simply be moved without causing lot’s of problems.
@Tomura
Moving stuff into different folder doesn’t solve the “space” problem.
I am aware that I’m becoming like an roman consul Kato who finished every one of his speech, doesn’t matter what that speech was about, crop failure, rising taxes, upcoming wars, political instability etc, with the sentence:
“Furthermore, I consider that Carthage must be destroyed”
I in the identical spirit, will say:
At this moment in time, there is something seriously wrong with UE4 with almost all of its aspects, which renders it totally unsuitable and unusable for any medium to large commercial project.
At this moment in time, UE4 is merely a toy, not a tool. And not even funny to play with.
It’s totally safe to delete DerivedDataCache; next time you open a project your shader code will have to recompile but that’s it.
DDC expands every time you change a material’s setup IIRC, to cache that data… Which means it quickly bloats with outdated/unreferenced shader code that nothing calls.
It’s annoying as hell (though more recent 4.7 preview builds seem better about it, and I’m not sure if it’s finally cleaning up after itself or what) but it can be resolved with a periodic deletion of the DerivedDataCache.