diff --git a/win32/build/confutils.js b/win32/build/confutils.js
index 328dd355cc6..acb4f3047f5 100644
--- a/win32/build/confutils.js
+++ b/win32/build/confutils.js
@@ -1690,6 +1690,9 @@ function ADD_SOURCES(dir, file_list, target, obj_dir)
 
 			var vc_incs = WshShell.Environment("Process").Item("INCLUDE").split(";")
 			for (i in vc_incs) {
+				if (!vc_incs[i].length) {
+					continue;
+				}
 				analyzer_base_flags += " -I " + "\"" + vc_incs[i] + "\"";
 			}