diff --git a/install/calculate b/install/calculate
index b6110af..4427cf4 100755
--- a/install/calculate
+++ b/install/calculate
@@ -5241,7 +5241,8 @@ sub umount_build_dirs{
 #------------------------------------------------------------------------------
 sub createiso{
 	#проверим что не запущен cl-builder
-	if(`mount | grep "on /mnt/builder/usr/calculate/share"`) {
+	if(`mount | grep "on /mnt/builder/usr/calculate/share"`
+	|| `mount | grep -c "devpts on /dev/pts "` != 1 ) {
 		printmes(gettext('Error')."! ");
 		printmes(gettext('Before proceeding, complete the program cl-builder')); printmes(".\n");
 		return "";