diff --git a/app/models/user.rb b/app/models/user.rb
index e27b0be18..3081b0f95 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -214,6 +214,7 @@ class User < ApplicationRecord
   end
 
   def merge(old_user)
+    raise "Merging same user, no way" if old_user.id == self.id
     transaction do
       old_user.dossiers.update_all(user_id: id)
       old_user.invites.update_all(user_id: id)
diff --git a/db/migrate/20221013142432_clean_pending_user_with_requested_merge_into_id_similar_to_their_id.rb b/db/migrate/20221013142432_clean_pending_user_with_requested_merge_into_id_similar_to_their_id.rb
new file mode 100644
index 000000000..597442bd2
--- /dev/null
+++ b/db/migrate/20221013142432_clean_pending_user_with_requested_merge_into_id_similar_to_their_id.rb
@@ -0,0 +1,5 @@
+class CleanPendingUserWithRequestedMergeIntoIdSimilarToTheirId < ActiveRecord::Migration[6.1]
+  def change
+    User.where('users.id = users.requested_merge_into_id').update_all(requested_merge_into_id: nil)
+  end
+end
diff --git a/spec/models/user_spec.rb b/spec/models/user_spec.rb
index a9715c397..75447ae94 100644
--- a/spec/models/user_spec.rb
+++ b/spec/models/user_spec.rb
@@ -423,7 +423,11 @@ describe User, type: :model do
     let(:targeted_user) { create(:user) }
 
     subject { targeted_user.merge(old_user) }
-
+    context 'merge myself' do
+      it 'fails' do
+        expect { old_user.merge(old_user) }.to raise_error 'Merging same user, no way'
+      end
+    end
     context 'and the old account has some stuff' do
       let!(:dossier) { create(:dossier, user: old_user) }
       let!(:hidden_dossier) { create(:dossier, user: old_user, hidden_by_user_at: 1.hour.ago) }