diff --git a/R/doeFactorial.R b/R/doeFactorial.R
index 5746e826..1312e667 100644
--- a/R/doeFactorial.R
+++ b/R/doeFactorial.R
@@ -337,7 +337,7 @@ doeFactorial <- function(jaspResults, dataset, options, ...) {
   df <- .doeRsmCategorical2df(options[["categoricalVariables"]])
   designSpec <- .doeFactorialGetSelectedDesign(jaspResults, options)
   if (length(designSpec) == 0) {
-    return()
+    stop("No generator provided.")
   }
   if (length(unique(df[["name"]])) != options[["numberOfCategorical"]]) {
     stop("Duplicate factor names are not allowed.")
diff --git a/R/doeResponseSurfaceMethodology.R b/R/doeResponseSurfaceMethodology.R
index 213d5475..e85689c5 100644
--- a/R/doeResponseSurfaceMethodology.R
+++ b/R/doeResponseSurfaceMethodology.R
@@ -378,6 +378,9 @@ doeResponseSurfaceMethodology <- function(jaspResults, dataset, options, ...) {
   if (!dir.exists(dirname(outpath)))
     return()
 
+  if (is.null(design))
+    return()
+
   out_design <- design
   colnames(out_design)[1:2] <- c("RunOrder", "StandardOrder")
   out_design[["Response"]] <- ""