diff --git a/app/controllers/courses_controller.rb b/app/controllers/courses_controller.rb
index 6f4b2e769..50444a018 100755
--- a/app/controllers/courses_controller.rb
+++ b/app/controllers/courses_controller.rb
@@ -553,6 +553,10 @@ def upload_roster
       begin
         save_uploaded_roster
         flash[:success] = "Successfully updated roster!"
+        unless @roster_warnings.nil?
+          w = @roster_warnings.keys.join('\n')
+          flash[:error] = w
+        end
         redirect_to(action: "users") && return
       rescue StandardError => e
         if e != "Roster validation error"
@@ -953,6 +957,8 @@ def write_cuds(cuds)
       rosterWarnings[msg].push(cud)
     end
 
+    @roster_warnings = rosterWarnings
+
     return if rosterErrors.empty?
 
     @roster_error = rosterErrors