Unreal Engine fails to start because RiderLink DLLs are blocked by WDAC. "Plugin 'RiderLink' failed to load because module 'RiderGameControl' could not be loaded"

Problem

When launching Unreal Engine 5.8 with RiderLink installed (via JetBrains Rider), Unreal Editor intermittently fails to start because the RiderLink plugin cannot be loaded.

Unreal Engine log shows errors similar to:

• Plugin 'RiderLink' failed to load because module 'RiderGameControl' could not be loaded. There may be an operating system error or the module may not be properly set up.

And then an assertion failure such as:

• Assertion failed: ModuleManager.IsModuleLoaded(ModuleName) ... Tried to get module interface for unloaded module: 'RiderLink'

Windows Event Viewer (Applications and Services Logs → Microsoft → Windows → CodeIntegrity → Operational) shows Code Integrity / WDAC-related blocks, e.g.:

• Event ID 3077 for UnrealEditor-RiderGameControl.dll : `Code Integrity determined that a process (\Device\HarddiskVolume3\Program Files\Epic Games\UE_5.8\Engine\Binaries\Win64\UnrealEditor.exe) attempted to load \Device\HarddiskVolume3\path\to\GameProjectName\Plugins\Developer\RiderLink\Binaries\Win64\UnrealEditor-RiderGameControl.dll that did not meet the Enterprise signing level requirements or violated code integrity policy (Policy ID:{id}).
• Event ID 3033 for UnrealEditor-RiderBlueprint.dll : Code Integrity determined that a process (\Device\HarddiskVolume3\Program Files\Epic Games\UE_5.8\Engine\Binaries\Win64\UnrealEditor.exe) attempted to load \Device\HarddiskVolume3\path\to\GameProjectName\Plugins\Developer\RiderLink\Binaries\Win64\UnrealEditor-RiderBlueprint.dll that did not meet the Enterprise signing level requirements
• Sometimes a different RiderLink DLL (e.g., RiderDebuggerSupport.dll) is the one reported as blocked

The affected system has Windows Smart App Control enabled (strict WDAC policy / UMCI behavior).

Cause

RiderLink is shipped by Rider as source code and is compiled locally by UnrealBuildTool (UBT) against the specific installed Unreal Engine version. The resulting RiderLink output DLLs are locally generated and unsigned by default.

In environments enforcing a strict Windows Defender Application Control (WDAC) policy with User Mode Code Integrity (UMCI) requirements, Windows blocks processes (including UnrealEditor.exe) from loading unsigned user-mode PE binaries (.dll / .exe).

This can appear intermittent because:

• Different projects may be in different locations (some paths may be permitted/whitelisted by policy while others are not).
• RiderLink consists of multiple peer modules (RiderBlueprint, RiderGameControl, RiderDebuggerSupport, etc.). The module that is attempted first can vary across reinstalls/builds (e.g., due to enumeration/load order), so a different DLL name may show up as the first blocked module even though all unsigned modules would be rejected.

Resolution

Use one (or more) of the following mitigations so that locally built RiderLink binaries are allowed under the active WDAC/Smart App Control policy:

1. Move the Unreal project to a trusted/allowed development directory

   If the current project resides under a more restricted location (for example under a user profile Desktop path like C:\Users\...\Desktop), move it to a directory that is known to be allowed by your organization’s policy (often something like C:\Dev\...).

2. Install RiderLink into the Unreal Engine (engine-level install) instead of project-level

   If the engine installation root (e.g., under C:\Program Files\...) is already covered by policy rules, install RiderLink at the engine level:

   • In Rider: Settings | Languages & Frameworks | Unreal Engine
   • Choose: Install plugin in Engine

3. Work with IT/Security to support local development under WDAC

   In enterprise environments, typical supported approaches are:

   • Maintain an explicitly whitelisted folder intended for development outputs.
   • Provide an internal code-signing certificate (PKI/AD CS) and require developers to sign locally built binaries so they meet the organization’s WDAC/UMCI signing requirements.