diff --git a/DESCRIPTION b/DESCRIPTION
index 404497a..ef06d1d 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,6 +1,6 @@
 Package: experDesign
 Title: Design Experiments for Batches
-Version: 0.3.0.9000
+Version: 0.3.0.9001
 Authors@R: c(
     person("Lluís", "Revilla Sancho", , "lluis.revilla@gmail.com", role = c("aut", "cre"),
            comment = c(ORCID = "0000-0001-9747-2570")),
diff --git a/R/indexing.R b/R/indexing.R
index 2933868..ace4b6a 100644
--- a/R/indexing.R
+++ b/R/indexing.R
@@ -73,6 +73,11 @@ create_index4index <- function(index, size_subset, n, name) {
       if (length(setdiff(pp, which(dups_out)))) {
         pp <- setdiff(pp, which(dups_out))
       }
+      # Somehow sometimes there is an error with sample!
+      if (is.null(pp)) {
+        next
+      }
+
       i_index <- sample(pp, 1)
       index_f <- c(index_f, i_index)