Quick answer: Unreal Shipping cook taking 6+ hours because of shader permutation explosion? Check ShaderPermutationReduction and exclude unused quality levels per platform.

Cooking iOS Shipping: 8 hours, 60% of which is shader compilation. Mostly variants no iOS device uses.

Exclude unused quality levels

DefaultGame.ini: sg.PostProcessQuality.Levels=2,3. Skips low/medium quality builds the iOS profile never selects.

Use Shader Permutation Reduction

Plugin in 5.3+. Profiles shader use in a representative gameplay session; trims unused permutations from the cook.

Profile with the shader stats

r.ShaderCompiler.PrintShaderStats 1. Shows per-shader permutation count; outliers stand out.

“Shader cooking is multiplicative. Trimming one axis trims a lot.”

Track shader cook time per build. Sudden growth correlates with a new material or post-process that exploded variants; track down before it lands.