diff --git a/app/controllers/study_groups_controller.rb b/app/controllers/study_groups_controller.rb
index 54ab1750..ce7a49f3 100644
--- a/app/controllers/study_groups_controller.rb
+++ b/app/controllers/study_groups_controller.rb
@@ -20,7 +20,7 @@ class StudyGroupsController < ApplicationController
 
   def update
     myparams = study_group_params
-    myparams[:users] = StudyGroupMembership.find(myparams[:study_group_membership_ids].reject(&:empty?)).map(&:user)
+    myparams[:external_users] = StudyGroupMembership.find(myparams[:study_group_membership_ids].reject(&:empty?)).map(&:user)
     myparams.delete(:study_group_membership_ids)
     update_and_respond(object: @study_group, params: myparams)
   end