diff --git a/tests/actions-test-lib.sh b/tests/actions-test-lib.sh
index 2530fb8..71cd4fd 100644
--- a/tests/actions-test-lib.sh
+++ b/tests/actions-test-lib.sh
@@ -20,7 +20,7 @@ make_action()
 {
     unset TODO_ACTIONS_DIR
     [ -d .todo.actions.d ] || mkdir .todo.actions.d
-    make_dummy_action ".todo.actions.d/$1"
+    [ -z "$1" ] || make_dummy_action ".todo.actions.d/$1"
 }
 
 make_action_in_folder()
@@ -28,5 +28,5 @@ make_action_in_folder()
     unset TODO_ACTIONS_DIR
     [ -d .todo.actions.d ] || mkdir .todo.actions.d
     mkdir ".todo.actions.d/$1"
-    make_dummy_action ".todo.actions.d/$1/$1" "in folder $1"
+    [ -z "$1" ] || make_dummy_action ".todo.actions.d/$1/$1" "in folder $1"
 }
diff --git a/tests/t8000-actions.sh b/tests/t8000-actions.sh
index 763c4e9..2facc8f 100755
--- a/tests/t8000-actions.sh
+++ b/tests/t8000-actions.sh
@@ -44,4 +44,50 @@ custom action bad
 === 42
 EOF
 
+make_action
+ln -s /actionsdir/doesnotexist/badlink .todo.actions.d/badlink
+# On Cygwin, the Windows ACL may still grant execution rights. In this case, we
+# skip the test.
+if [ -x .todo.actions.d/badlink ]; then
+    SKIP_TESTS="${SKIP_TESTS}${SKIP_TESTS+ }t8000.6 t8000.7"
+fi
+test_todo_session 'broken symlink' <<EOF
+>>> todo.sh badlink | sed "s#'[^']*\(\\.todo\\.actions\\.d/[^']\{1,\}\)'#'\1'#g"
+Fatal Error: Broken link to custom action: '.todo.actions.d/badlink'
+
+>>> todo.sh do >/dev/null
+=== 1
+EOF
+
+make_action
+mkdir .todo.actions.d/badfolderlink
+ln -s /actionsdir/doesnotexist/badfolderlink .todo.actions.d/badfolderlink/badfolderlink
+# On Cygwin, the Windows ACL may still grant execution rights. In this case, we
+# skip the test.
+if [ -x .todo.actions.d/badfolderlink/badfolderlink ]; then
+    SKIP_TESTS="${SKIP_TESTS}${SKIP_TESTS+ }t8000.8 t8000.9"
+fi
+test_todo_session 'broken symlink in folder' <<EOF
+>>> todo.sh badfolderlink | sed "s#'[^']*\(\\.todo\\.actions\\.d/[^']\{1,\}\)'#'\1'#g"
+Fatal Error: Broken link to custom action: '.todo.actions.d/badfolderlink/badfolderlink'
+
+>>> todo.sh do >/dev/null
+=== 1
+EOF
+
+make_action
+ln -s /actionsdir/doesnotexist/do .todo.actions.d/do
+# On Cygwin, the Windows ACL may still grant execution rights. In this case, we
+# skip the test.
+if [ -x .todo.actions.d/do ]; then
+    SKIP_TESTS="${SKIP_TESTS}${SKIP_TESTS+ }t8000.10 t8000.11"
+fi
+test_todo_session 'broken symlink overrides built-in action' <<EOF
+>>> todo.sh do | sed "s#'[^']*\(\\.todo\\.actions\\.d/[^']\{1,\}\)'#'\1'#g"
+Fatal Error: Broken link to custom action: '.todo.actions.d/do'
+
+>>> todo.sh do >/dev/null
+=== 1
+EOF
+
 test_done
diff --git a/todo.sh b/todo.sh
index 37eca5e..f128e67 100755
--- a/todo.sh
+++ b/todo.sh
@@ -1038,7 +1038,13 @@ listWordsWithSigil()
 
 hasCustomAction()
 {
-    [ -d "${1:?}" ] && [ -x "${1:?}/${2:?}" ]
+    [ -d "${1:?}" ] || return 1
+    [ -x "$1/${2:?}" ] && return 0
+    if [ -h "$1/$2" ] && [ ! -e "$1/$2" ]
+    then
+        dieWithHelp "$2" "Fatal Error: Broken link to custom action: '$1/$2'"
+    fi
+    return 1
 }
 
 export -f cleaninput getPrefix getTodo getNewtodo shellquote filtercommand _list listWordsWithSigil getPadding _format die