Unreal Engine Derived Data Cache (Engine/DerivedDataCache & LocalDDC)

Bottom Line: It is 100% safe to delete Unreal Engine DerivedDataCache (DDC). Unreal Engine automatically regenerates derived asset caches when you open a project in the Unreal Editor.

Why Does Unreal Engine DDC Exist?

Unreal Engine 5 (UE5) transforms raw source assets (TGA images, FBX 3D models, audio files) into engine-optimized formats (compressed HLSL shaders, Nanite streaming geometry, distance fields) stored in DerivedDataCache (DDC).

• Primary Purpose: Caching compressed Nanite meshes, Lumen global illumination data, and compiled HLSL shaders.
• Storage Growth: DDC directories accumulate gigabytes of derived data across engine versions (UE 5.3, 5.4, 5.5), consuming 20 GB to 100 GB+.
• Location: Stored in %LocalAppData%\UnrealEngine\Common\DerivedDataCache or project DerivedDataCache/ directories.

What Happens If You Delete Unreal Engine DDC?

• System Safety: ✅ 100% Safe to Delete. Source assets inside Content/ (.uasset) and C++ code are untouched.
• Initial Project Open Delay: The next time you open the Unreal Editor, a “Compiling Shaders” progress bar will display while DDC is rebuilt.
• Reclaimed Storage: Reclaims 20 GB to 100 GB+ of SSD space.

How to Delete Unreal Engine DDC Safely

# Delete global Unreal Engine DDC cache
Remove-Item -Path "$env:LOCALAPPDATA\UnrealEngine\Common\DerivedDataCache\*" -Recurse -Force -ErrorAction SilentlyContinue

# Delete project-level DDC
Remove-Item -Path "C:\MyUnrealProject\DerivedDataCache\*" -Recurse -Force -ErrorAction SilentlyContinue

Frequently Asked Questions (FAQ)

How do I set up a Shared DDC for a game dev team?

In team environments, configure DefaultEngine.ini to point SharedDDC to a fast network drive so team members don’t recompile shaders individually.