diff --git a/R/create_DataFile.R b/R/create_DataFile.R
index a91499c..fc83939 100644
--- a/R/create_DataFile.R
+++ b/R/create_DataFile.R
@@ -161,7 +161,7 @@ create_DataFile <- function(
 
     } else {
       ## import files as specified -------
-      out <- lapply(suppressWarnings(normalizePath(tolower(config[[x]]$files))), function(x) {
+      out <- lapply(suppressWarnings(normalizePath(config[[x]]$files)), function(x) {
         if (!file.exists(x))
           stop(paste0("[create_DataFile()] file <", x, "> does not exist!"), call. = FALSE)