UEFN 43.00 fails to launch because Windows Smart App Control blocks its bundled dxcompiler.dll, causing ShaderCompileWorker to crash even after file verification.

General Issues and Bug Reporting
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Hi @leoel

This was a problem long while ago and its parts of Windows Defender.

UEFN/Fortnite flagged as Malware from Microsoft Defender - General / Issues and Bug Reporting - Epic Developer Community Forums

This needed to be added to the Windows Defender exception list as in the past thread