diff --git a/cmake/build_helpers.cmake b/cmake/build_helpers.cmake
index 57e16ab6c..a165846e8 100644
--- a/cmake/build_helpers.cmake
+++ b/cmake/build_helpers.cmake
@@ -641,10 +641,12 @@ function(downloadImHexPatternsFiles dest)
             endforeach()
         ]])
     else()
-        set(PATTERNS_FOLDERS_TO_INSTALL constants encodings includes patterns magic nodes)
-        foreach (FOLDER ${PATTERNS_FOLDERS_TO_INSTALL})
-            install(DIRECTORY "${imhex_patterns_SOURCE_DIR}/${FOLDER}" DESTINATION "${dest}" PATTERN "**/_schema.json" EXCLUDE)
-        endforeach ()
+        if (NOT (imhex_patterns_SOURCE_DIR STREQUAL ""))
+            set(PATTERNS_FOLDERS_TO_INSTALL constants encodings includes patterns magic nodes)
+            foreach (FOLDER ${PATTERNS_FOLDERS_TO_INSTALL})
+                install(DIRECTORY "${imhex_patterns_SOURCE_DIR}/${FOLDER}" DESTINATION "${dest}" PATTERN "**/_schema.json" EXCLUDE)
+            endforeach ()
+        endif()
     endif ()
 
 endfunction()