diff --git a/src/Cake.ProtobufTools.Tests/Protoc/ProtocAliasesTest.cs b/src/Cake.ProtobufTools.Tests/Protoc/ProtocAliasesTest.cs
index d160f3b..5110d39 100644
--- a/src/Cake.ProtobufTools.Tests/Protoc/ProtocAliasesTest.cs
+++ b/src/Cake.ProtobufTools.Tests/Protoc/ProtocAliasesTest.cs
@@ -16,7 +16,7 @@ public void WhenCSharpAndOFileAreSet_CommandLineIsCorrect()
             };
 
             var actual = fixture.Run();
-            Assert.That(actual.Args, Is.EqualTo("-oFILE --csharp_out=\"some_folder\" definitions.proto"));
+            Assert.That(actual.Args, Is.EqualTo("-oFILE --csharp_out=\"some_folder\" \"definitions.proto\""));
         }
     }
 }
diff --git a/src/Cake.ProtobufTools/ArgumentsBuilderExtension.cs b/src/Cake.ProtobufTools/ArgumentsBuilderExtension.cs
index 9744019..7b68f43 100644
--- a/src/Cake.ProtobufTools/ArgumentsBuilderExtension.cs
+++ b/src/Cake.ProtobufTools/ArgumentsBuilderExtension.cs
@@ -40,7 +40,7 @@ public static void AppendAll<TSettings>(this ProcessArgumentBuilder builder, TSe
             {
                 foreach (string argument in arguments)
                 {
-                    builder.Append(argument);
+                    builder.AppendQuoted(argument);
                 }
             }
         }
diff --git a/src/Cake.ProtobufTools/ProtobufTools`1.cs b/src/Cake.ProtobufTools/ProtobufTools`1.cs
index 530c4cd..8975e18 100644
--- a/src/Cake.ProtobufTools/ProtobufTools`1.cs
+++ b/src/Cake.ProtobufTools/ProtobufTools`1.cs
@@ -43,10 +43,10 @@ public void Run(ProtocSettings settings, string[] additional)
             Run(settings, GetArguments(settings, additional));
         }
 
-        private ProcessArgumentBuilder GetArguments(ProtocSettings settings, string[] containers)
+        private ProcessArgumentBuilder GetArguments(ProtocSettings settings, string[] files)
         {
             var builder = new ProcessArgumentBuilder();
-            builder.AppendAll(settings, containers);
+            builder.AppendAll(settings, files);
             return builder;
         }