diff --git a/R/prepare_data2fit.R b/R/prepare_data2fit.R
index e10e1fdd821ace2ec6ee518f75249d35ffe809ed..660e3de9a0807af09ce12f416f5d1d20703dcafd 100644
--- a/R/prepare_data2fit.R
+++ b/R/prepare_data2fit.R
@@ -142,6 +142,8 @@ custom_matrix_transform <- function(count_matrix, custom_expression) {
 prepareData2fit <- function(countMatrix, metadata, response_name = "kij", 
                             groupID = "geneID", row_threshold = 0, transform = NULL , 
                             normalization = NULL) {
+  ## -- first check
+  stopifnot("<countMatrix> and <metadata> dimensions do not match!" = dim(countMatrix)[2] == dim(metadata)[1] )
   
   stopifnot( length(row_threshold) == 1 && is.numeric(row_threshold) && row_threshold >= 0  )
   if (row_threshold > 0){          
diff --git a/dev/flat_full.Rmd b/dev/flat_full.Rmd
index 742804ca54d617435c8fbc4754f3c0f536ce9a0c..b9d8dc1bed6b21cf78189cfae4735d37f5dab284 100644
--- a/dev/flat_full.Rmd
+++ b/dev/flat_full.Rmd
@@ -2801,6 +2801,8 @@ custom_matrix_transform <- function(count_matrix, custom_expression) {
 prepareData2fit <- function(countMatrix, metadata, response_name = "kij", 
                             groupID = "geneID", row_threshold = 0, transform = NULL , 
                             normalization = NULL) {
+  ## -- first check
+  stopifnot("<countMatrix> and <metadata> dimensions do not match!" = dim(countMatrix)[2] == dim(metadata)[1] )
   
   stopifnot( length(row_threshold) == 1 && is.numeric(row_threshold) && row_threshold >= 0  )
   if (row_threshold > 0){          
diff --git a/vignettes/02-tutorial.Rmd b/vignettes/02-tutorial.Rmd
index 966cd962502056391430e9a4add889a81bb649b8..3eeb443249441698354ea94f4d1fd8d0f40cc31c 100644
--- a/vignettes/02-tutorial.Rmd
+++ b/vignettes/02-tutorial.Rmd
@@ -15,7 +15,6 @@ knitr::opts_chunk$set(
 ```
 
 ```{r setup}
-devtools::load_all()
 library(HTRfit)
 ```