diff --git a/lib/pact/provider/pact_uri.rb b/lib/pact/provider/pact_uri.rb
index 1a43ed03..3bb4107b 100644
--- a/lib/pact/provider/pact_uri.rb
+++ b/lib/pact/provider/pact_uri.rb
@@ -29,10 +29,10 @@ def password
       end
 
       def to_s
-        if(basic_auth?)
+        if basic_auth? && uri.start_with?('http://', 'https://')
           URI(@uri).tap { |x| x.userinfo="#{username}:*****"}.to_s
         else
-          @uri
+          uri
         end
       end
     end
diff --git a/spec/lib/pact/provider/pact_uri_spec.rb b/spec/lib/pact/provider/pact_uri_spec.rb
index 357e88de..162acbde 100644
--- a/spec/lib/pact/provider/pact_uri_spec.rb
+++ b/spec/lib/pact/provider/pact_uri_spec.rb
@@ -30,6 +30,14 @@
       it 'should include user name and password' do
         expect(pact_uri.to_s).to eq('http://pact:*****@uri')
       end
+
+      context 'when basic auth credentials have been set for a local file (eg. via environment variables, unintentionally)' do
+        let(:uri) { '/some/file thing.json' }
+
+        it 'does not blow up' do
+          expect(pact_uri.to_s).to eq uri
+        end
+      end
     end
 
     context 'without userinfo' do