diff --git a/tools/quartus/set_quartus b/tools/quartus/set_quartus
index 90fc3c2bc793723f36cff3439b09fecf6cd1ae79..ba7162bdd3722494b53e74b2730c6c930cfdd61c 100755
--- a/tools/quartus/set_quartus
+++ b/tools/quartus/set_quartus
@@ -41,6 +41,16 @@ if [ "${SITE-}" = "USN" ]; then
   export LC_MESSAGES=C
 
   if [ "${TOOLSET}" = "unb1" ]; then
+    # check if locale en_US (en_US.iso88591 is present.  If not, it will throw error like:
+    # Warning: sopc_unb1_minimal.: /home/software/Altera/11.1sp2/quartus/adm/qenv.sh: line 87: setlocale: LC_CTYPE: cannot change locale (en_US): No such file or directory
+    locale -a | grep -q "en_US.iso88591"
+    if [ $? -ne 0 ] ; then
+      echo "Missing locale en_US.iso88591 required by some Quartus scripts"
+      echo "Install with:"
+      echo "> sudo locale-gen en_US"
+      exit 1
+    fi
+    
     . ${RADIOHDL}/tools/quartus/quartus_version.sh 11.1sp2
   elif [ "${TOOLSET}" = "unb2" ]; then
     . ${RADIOHDL}/tools/quartus/quartus_version.sh 14.1
@@ -50,6 +60,7 @@ if [ "${SITE-}" = "USN" ]; then
   fi
   # chech that ipx file is correctly setup
   ${RADIOHDL}/tools/quartus/check_ipx_content
+
 else # default site
   if [ "${TOOLSET}" = "unb1" ]; then
     . ${RADIOHDL}/tools/quartus/quartus_version.sh 11.1