DerivedDataCache - 3 GB on C:

My colleague and I are wondering if it would not be possible to have C: - ProgramData - Epic be moved elsewhere?

The folder DerivedDataCache within that folder in particular is huge. We run SSD drives for C:\ that hold nothing more than the OS, and we’ve specifically moved away temp folders from C:\ also to save space/fewer write operations to the SSD’s but we are stuck with this Epic folder.

  1. Can’t you make the location user defined?
  2. Can we delete the DerivedDataCache? What happens then?

Yes, you can use any cache hierarchy you like for the DDC.


; Derived Data backend graphs
; Each of the below backend graph sections contains a set of nodes used to create derived data backed graph.
; DerivedDataBackendGraph is the default graph and the other can be specified in the command line using:

In the BaseEngine.ini file. I beleive you will normally be using RocketDerivedDataBackendGraph, but the other ones have useful examples.

You can delete the DDC. You will have to rebuild some assets if you do. Migrations of DDCs is also possible with some clever cache hierarchies. For example, DerivedDataBackendGraph migrates from AltShared to Shared.

That worked, thank you. Just changed every path with deriveddatacache to the new path.
Don’t forget to add " " if you have spaces in the directory.

Boot=(Type=Boot, Filename=“D:/Program Files/Unreal Engine Projects/DerivedDataCache/Boot.ddc”, MaxCacheSize=512)

FoldersToClean=-1, Path=“D:/Program Files/Unreal Engine Projects/DerivedDataCache

Pak=(Type=ReadPak, Filename=“D:/Program Files/Unreal Engine Projects/DerivedDataCache/DDC.ddp”)

EnginePak=(Type=ReadPak, Filename=“D:/Program Files/Unreal Engine Projects/DerivedDataCache/DDC.ddp”)