Fix for Unreal Engine 5.7/5.7.1 DDC Cache Error

Development Getting Started & Setup
1

Hello,

I had already posted a small solution to the launch crash of 5.7, so I’m doing the same thing for 5.7.1.

Error Message

“ Fatal error: [File:D:\build\++UE5\Sync\Engine\Source\Developer\DerivedDataCache\Private\DerivedDataBackends.cpp] [Line: 208] Unable to use default cache graph ‘InstalledDerivedDataBackendGraph’ because there are no writable nodes available. Add -DDC-ForceMemoryCache … “

Solution 1: Delete Corrupted Cache Folders (Try This First)

This issue often occurs after updating UE (e.g., 5.7.0 → 5.7.1) due to corrupted cache files.

Steps:

  1. Close Unreal Engine completely (including Epic Games Launcher if running)

  2. Navigate to C:\Users\[YourUsername]\AppData\Local\UnrealEngine\Common

    • Delete the Zen folder

  3. Navigate to C:\Users\[YourUsername]\AppData\Local\UnrealEngine

    • Delete the DerivedDataCache folder

  4. Restart Unreal Engine 5.7/5.7.1

    • The folders will be recreated automatically

    • First launch will compile shaders (this is normal and takes time)

    • Subsequent launches will be faster

Note: If you can’t find the AppData folder, make sure hidden folders are visible in Windows Explorer (View → Show → Hidden items)

Solution 2: Fix BaseEngine.ini Configuration (If Solution 1 Doesn’t Work)

If deleting cache folders doesn’t resolve the issue, the problem may be in the engine configuration file.

Steps:

  1. Navigate to your UE installation folder:

    • Default: C:\Program Files\Epic Games\UE_5.7\Engine\Config

    • Or if installed elsewhere: [YourInstallPath]\UE_5.7\Engine\Config

  2. Open BaseEngine.ini with a text editor (Notepad++, VS Code, or Notepad)

  3. Use Find & Replace (Ctrl + H):

    • Find: DeleteOnly=true

    • Replace with: DeleteOnly=false

    • Click Replace All (should replace 4-5 instances)

  4. Save the file and close the editor

  5. Launch Unreal Engine 5.7/5.7.1

Alternative Installation Path Solution

Some users have reported success by installing UE on a secondary drive with full permissions:

  1. Uninstall UE 5.7 from C:\Program Files\Epic Games

  2. Reinstall to a secondary drive (e.g., E:\Epic Games\UE_5.7)

  3. Delete cache folders as described in Solution 1

  4. Launch UE

Temporary Workaround (Not Recommended for Production)

If you need to launch UE immediately without fixing the cache:

Add -DDC-ForceMemoryCache to the launch parameters:

  • In Epic Games Launcher, click the dropdown next to “Launch”

  • Select “Options”

  • Add -DDC-ForceMemoryCache to command line arguments

Warning: This will recompile all shaders every time you launch the engine, significantly increasing load times.

Why Does This Happen?

The Derived Data Cache (DDC) stores compiled shaders and other processed assets. When:

  • UE updates versions (5.7.0 → 5.7.1), cache files can become incompatible

  • The BaseEngine.ini has DeleteOnly=true, it prevents writing to the cache

  • Cache folders become corrupted during updates

This results in no writable cache nodes being available, causing the engine to crash on startup.

Community Contribution

This solution was discovered through community troubleshooting. If this helped you, please share with others experiencing the same issue!

Tested on:

  • Unreal Engine 5.7.0

  • Unreal Engine 5.7.1

  • Windows 10/11

Last Updated: December 2024

2 Likes
2

I’ve had a headache for a while…

The problem is finally solved.

Thank you so much… ^^