diff --git a/app/services/projects/hashed_storage/migrate_attachments_service.rb b/app/services/projects/hashed_storage/migrate_attachments_service.rb
index 68b9a72661c..26026899ebe 100644
--- a/app/services/projects/hashed_storage/migrate_attachments_service.rb
+++ b/app/services/projects/hashed_storage/migrate_attachments_service.rb
@@ -1,5 +1,7 @@
 module Projects
   module HashedStorage
+    AttachmentMigrationError = Class.new(StandardError)
+
     class MigrateAttachmentsService < BaseService
       attr_reader :logger
 
@@ -27,7 +29,7 @@ module Projects
 
         if File.exist?(new_path)
           logger.error("Cannot migrate attachments from '#{old_path}' to '#{new_path}', target path already exist (PROJECT_ID=#{project.id})")
-          return
+          raise AttachmentMigrationError, "Target path '#{new_path}' already exist"
         end
 
         # Create hashed storage base path folder
diff --git a/spec/services/projects/hashed_storage/migrate_attachments_service_spec.rb b/spec/services/projects/hashed_storage/migrate_attachments_service_spec.rb
index ce43a7e4d54..de2abfc1985 100644
--- a/spec/services/projects/hashed_storage/migrate_attachments_service_spec.rb
+++ b/spec/services/projects/hashed_storage/migrate_attachments_service_spec.rb
@@ -49,13 +49,10 @@ describe Projects::HashedStorage::MigrateAttachmentsService do
         FileUtils.mkdir_p(base_path(hashed_storage))
       end
 
-      it 'skips moving the file and goes to next' do
+      it 'raises AttachmentMigrationError' do
         expect(FileUtils).not_to receive(:mv).with(base_path(legacy_storage), base_path(hashed_storage))
 
-        service.execute
-
-        expect(File.exist?(base_path(legacy_storage))).to be_truthy
-        expect(File.file?(old_path)).to be_truthy
+        expect { service.execute }.to raise_error(Projects::HashedStorage::AttachmentMigrationError)
       end
     end
   end