diff --git a/CHANGELOG.md b/CHANGELOG.md
index 557e539..ec8b588 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,7 @@ Record of the modification in project development.
 ### Changed
 - [Issue 5 : OVERWRITEINSTALL confirmation is missing](https://github.com/suikan4github/kaiten-yaki/issues/5)
 - [Issue 6 : Remove loglevel dependency from the void-kaiten-yaki.sh ](https://github.com/suikan4github/kaiten-yaki/6)
+- [Issue 7 : Add the return status validation ](https://github.com/suikan4github/kaiten-yaki/7)
 
 ### Deprecated
 ### Removed
diff --git a/script/lib.sh b/script/lib.sh
index 0d03ad7..82b0ffc 100644
--- a/script/lib.sh
+++ b/script/lib.sh
@@ -138,27 +138,33 @@ function pre_install() {
 			# Zap existing partition table and create new GPT
 			echo "...Initializing \"${DEV}\" with GPT."
 			sgdisk --zap-all "${DEV}"
+			if is_error ; then return 1 ; fi; 	# If error, terminate
 			# Create EFI partition and format it
 			echo "...Creating an EFI partition on \"${DEV}\"."
 			# shellcheck disable=SC2140
 			sgdisk --new="${EFIPARTITION}":0:+"${EFISIZE}" --change-name="${EFIPARTITION}":"EFI System"  --typecode="${EFIPARTITION}":ef00 "${DEV}"  
+			if is_error ; then return 1 ; fi; 	# If error, terminate
 			echo "...Formatting the EFI parttion."
 			mkfs.vfat -F 32 -n EFI-SP "${DEV}${EFIPARTITION}"
+			if is_error ; then return 1 ; fi; 	# If error, terminate
 			# Create Linux partition
 			echo "...Creating a Linux partition on ${DEV}."
 			# shellcheck disable=SC2140
 			sgdisk --new="${CRYPTPARTITION}":0:0    --change-name="${CRYPTPARTITION}":"Linux LUKS" --typecode="${CRYPTPARTITION}":8309 "${DEV}"
+			if is_error ; then return 1 ; fi; 	# If error, terminate
 			# Then print them
 			sgdisk --print "${DEV}"
 		else # BIOS
 			# Zap existing partition table
 			echo "...Erasing partition table of \"${DEV}\"."
 			dd if=/dev/zero of="${DEV}" bs=512 count=1
+			if is_error ; then return 1 ; fi; 	# If error, terminate
 			# Create MBR and allocate max storage for Linux partition
 			echo "...Creating a Linux partition on ${DEV} with MBR."
 			sfdisk "${DEV}" <<- HEREDOC
 			2M,,L
 			HEREDOC
+			if is_error ; then return 1 ; fi; 	# If error, terminate
 		fi	# if EFI firmware
 
 		# Encrypt the partition to install Linux
@@ -194,8 +200,10 @@ function pre_install() {
 	else
 		echo "...Initializing a physical volume on \"${CRYPTPARTNAME}\""
 		pvcreate /dev/mapper/"${CRYPTPARTNAME}"
+		if [ $? -ne 0 ] ; then deactivate_and_close; return 1 ; fi;
 		echo "...And then creating Volume group \"${VGNAME}\"."
 		vgcreate "${VGNAME}" /dev/mapper/"${CRYPTPARTNAME}"
+		if [ $? -ne 0 ] ; then deactivate_and_close; return 1 ; fi;
 	fi # if /dev/volume-groupt exist
 
 	# Create a SWAP Logical Volume on VG, if it doesn't exist
@@ -204,6 +212,7 @@ function pre_install() {
 	else
 		echo "...Creating logical volume \"${LVSWAPNAME}\" on \"${VGNAME}\"."
 		lvcreate -L "${LVSWAPSIZE}" -n "${LVSWAPNAME}" "${VGNAME}" 
+		if [ $? -ne 0 ] ; then deactivate_and_close; return 1 ; fi;
 	fi	# if /dev/mapper/swap volume already exit. 
 
 	# Create a ROOT Logical Volume on VG. 
@@ -231,6 +240,7 @@ function pre_install() {
 		else # not exist and not overwrite install
 			echo "...Creating logical volume \"${LVROOTNAME}\" on \"${VGNAME}\"."
 			lvcreate -l "${LVROOTSIZE}" -n "${LVROOTNAME}" "${VGNAME}"
+			if [ $? -ne 0 ] ; then deactivate_and_close; return 1 ; fi;
 		fi
 	fi
 
@@ -331,4 +341,21 @@ function distribution_check(){
 
 	# no error
 	return 0
+}
+
+
+# ******************************************************************************* 
+#              Error report and return revsers status.  
+# ******************************************************************************* 
+function is_error() {
+	if [ $? -eq 0 ] ; then # Is previous job OK? 
+		return 1	# If OK, return error ( because it was not error )
+	else
+		cat <<- HEREDOC
+		**** ERROR ! ****
+
+		Installation process terminated. 
+		HEREDOC
+		return 0	# If error, return OK ( because it was error )
+	fi;
 }
\ No newline at end of file
diff --git a/script/void-kaiten-yaki.sh b/script/void-kaiten-yaki.sh
index 6dd8da4..87cfcd4 100644
--- a/script/void-kaiten-yaki.sh
+++ b/script/void-kaiten-yaki.sh
@@ -56,8 +56,8 @@ function main() {
 	# Common part of the pre-install stage
 	if ! pre_install ; then
 		# If error, restore the modification.
-		echo "...restoring modified /etc/default/grub."
-		sed -i -e "s#loglevel=4 ${GRUB_ADDITIONAL_PARAMETERS}#loglevel=4#" /etc/default/grub
+		echo "...restoring /etc/default/grub, if needed"
+		sed -i -e "s#${GRUB_ADDITIONAL_PARAMETERS}##" /etc/default/grub
 		return 1 # with error status
 	fi