diff --git a/admin/common b/admin/common
--- a/admin/common
+++ b/admin/common
@@ -1,58 +1,58 @@
 # -*- shell-script -*-
 #
 # Author: Gerwin Klein
 #
 # shell library functions common to the AFP scripts
 # assumes all AFP bash scripts are in admin/
 #
 
 PRG="$(basename "$0")"
 DIR="$(dirname "$0")"
 
 AFP_ROOT="$(cd "${DIR}/.."; pwd)"
 THYS="$AFP_ROOT/thys"
 
 source "$AFP_ROOT/etc/version"
 
 ##
 
 fail()
 {
   echo "### $1" >&2
   exit 2
 }
 
 timestamp()
 {
    echo "[timestamp: $(date "+%Y-%m-%d %H:%M:%S")]"
 }
 
 check_isabelle()
 {
   [ -x "$ISABELLE_TOOL" ] || fail "No isabelle tool wrapper found at [$ISABELLE_TOOL]."
   ISABELLE_HOME="$("$ISABELLE_TOOL" getenv -b ISABELLE_HOME)" || fail "could not find Isabelle home"
 }
 
 
 default_isabelle_tool()
 {
   if [ ! -x "$ISABELLE_TOOL" ]; then
     if [[ "$VERSION" == devel ]]; then
       ISABELLE_TOOL="$(which isabelle)"
     else
       [ "$ISABELLE_RELEASES" == "" ] && fail "ISABELLE_RELEASES not set"
       ISABELLE_VERSION="Isabelle$VERSION"
       ISABELLE_TOOL="$ISABELLE_RELEASES/$ISABELLE_VERSION/bin/isabelle"
       if [[ "$OSTYPE" == darwin* && ! -x "$ISABELLE_TOOL" ]]; then
-        ISABELLE_TOOL="$ISABELLE_RELEASES/${ISABELLE_VERSION}.app/Isabelle/bin/isabelle"
+        ISABELLE_TOOL="$ISABELLE_RELEASES/${ISABELLE_VERSION}.app/bin/isabelle"
       fi
     fi
   fi
 }
 
 set_isabelle_tool()
 {
   default_isabelle_tool
   check_isabelle
   echo "using [$ISABELLE_TOOL]"
 }