diff --git a/Wolf-tutorial-with-the-OBITools3.md b/Wolf-tutorial-with-the-OBITools3.md
index ed31ca4..be268da 100644
--- a/Wolf-tutorial-with-the-OBITools3.md
+++ b/Wolf-tutorial-with-the-OBITools3.md
@@ -126,7 +126,11 @@ For EMBL files, you can give the path to a directory with several EMBL files.
 3. Download the taxonomy:
 
 		wget https://ftp.ncbi.nlm.nih.gov/pub/taxonomy/taxdump.tar.gz
-		
+
+  Check the md5, as files downloaded from the NCBI are often corrupted on some networks. Compare https://ftp.ncbi.nlm.nih.gov/pub/taxonomy/taxdump.tar.gz.md5 with:
+
+		md5sum taxdump.tar.gz
+
 4. Import the taxonomy in the DMS:
 
 		obi import --taxdump taxdump.tar.gz wolf/taxonomy/my_tax