diff --git a/lib/tasks/s3.rake b/lib/tasks/s3.rake
index 8242493a680..a26c89ec743 100644
--- a/lib/tasks/s3.rake
+++ b/lib/tasks/s3.rake
@@ -67,7 +67,7 @@ def upload_asset(helper, path, recurse: true, content_type: nil, fullpath: nil,
 end
 
 def assets
-  cached = Rails.application.assets.cached
+  cached = Rails.application.assets&.cached
   manifest = Sprockets::Manifest.new(cached, Rails.root + 'public/assets', Rails.application.config.assets.manifest)
 
   raise Discourse::SiteSettingMissing.new("s3_upload_bucket") if SiteSetting.s3_upload_bucket.blank?