diff --git a/spec/bundler/spec_helper.rb b/spec/bundler/spec_helper.rb
index f0d6bce006..fad1d4ce32 100644
--- a/spec/bundler/spec_helper.rb
+++ b/spec/bundler/spec_helper.rb
@@ -139,4 +139,11 @@ RSpec.configure do |config|
       metadata[tag] = true
     end
   end
+
+  config.before(:context) do |example|
+    metadata = example.class.metadata
+    if metadata[:type] != :aruba && metadata.keys.none? {|k| Spec::WindowsTagGroup::EXAMPLE_MAPPINGS.keys.include?(k) }
+      warn "#{metadata[:file_path]} is not assigned to any Windows runner group. see spec/support/windows_tag_group.rb for details."
+    end
+  end
 end
diff --git a/spec/bundler/support/windows_tag_group.rb b/spec/bundler/support/windows_tag_group.rb
index 77112a2c6c..8eb0a749da 100644
--- a/spec/bundler/support/windows_tag_group.rb
+++ b/spec/bundler/support/windows_tag_group.rb
@@ -1,5 +1,10 @@
 # frozen_string_literal: true
 
+# This group classifies test files into 4 groups by running `bin/rspec --profile 10000`
+# to ensure balanced execution times. When adding new test files, it is recommended to
+# re-aggregate and adjust the groups to keep them balanced.
+# For now, please add new files to group 'windows_d'.
+
 module Spec
   module WindowsTagGroup
     EXAMPLE_MAPPINGS = {