diff --git a/bin/_stack_lib.sh b/bin/_stack_lib.sh
index 3c4ad2c..d7d8b8f 100755
--- a/bin/_stack_lib.sh
+++ b/bin/_stack_lib.sh
@@ -76,7 +76,7 @@ function create_self_deleting_tempdir() {
   case $(uname -s) in
     Darwin )
       : ${TMPDIR:=/tmp} ;
-      filename=$(mktemp -d -t _stacklib_ )
+      filename=$(mktemp -d -t _stacklib_.XXXXXXXX )
       ;;
     Linux | CYGWIN* )
       filename=$(mktemp -d)
@@ -100,7 +100,7 @@ function make_self_deleting_tempfile() {
   case $(uname -s) in
     Darwin )
       : ${TMPDIR:=/tmp} ;
-      name=$(mktemp -t _stacklib_ )
+      name=$(mktemp -t _stacklib_.XXXXXXXX )
       ;;
     Linux | CYGWIN* )
       name=$(mktemp)
@@ -122,7 +122,7 @@ function make_tempdir() {
   case $(uname -s) in
     Darwin )
       : ${TMPDIR:=/tmp} ;
-      name=$(mktemp -d -t _stacklib_ )
+      name=$(mktemp -d -t _stacklib_.XXXXXXXX )
       ;;
     Linux | CYGWIN* )
       name=$(mktemp -d)