diff --git a/runtime/runtime.cmake b/runtime/runtime.cmake
index ec1f18a4..70d94d5f 100644
--- a/runtime/runtime.cmake
+++ b/runtime/runtime.cmake
@@ -801,6 +801,13 @@ function(psxrecomp_add_runtime_target target)
     # to; copy_directory merges rather than replacing the tree.
     if(EXISTS "${PSXRECOMP_ROOT}/mods/builtin/packages")
         add_custom_command(TARGET ${target} POST_BUILD
+            # Clear first: copy_directory MERGES, so a mod deleted from source
+            # would otherwise survive in the build output forever and keep
+            # appearing on the Mods page (and inflate the release packagers'
+            # catalog assertions). This runs before the game's own staging, so
+            # both catalogs land on a clean slate.
+            COMMAND ${CMAKE_COMMAND} -E rm -rf
+                "$<TARGET_FILE_DIR:${target}>/mods"
             COMMAND ${CMAKE_COMMAND} -E copy_directory
                 "${PSXRECOMP_ROOT}/mods/builtin"
                 "$<TARGET_FILE_DIR:${target}>/mods"