diff --git a/gio/gsubprocess.c b/gio/gsubprocess.c
index 23bfbddf2..dcdb84d58 100644
--- a/gio/gsubprocess.c
+++ b/gio/gsubprocess.c
@@ -1784,6 +1784,9 @@ g_subprocess_communicate_finish (GSubprocess   *subprocess,
  *
  * Like g_subprocess_communicate(), but validates the output of the
  * process as UTF-8, and returns it as a regular NUL terminated string.
+ *
+ * On error, @stdout_buf and @stderr_buf will be set to undefined values and
+ * should not be used.
  */
 gboolean
 g_subprocess_communicate_utf8 (GSubprocess   *subprocess,
@@ -1868,6 +1871,7 @@ communicate_result_validate_utf8 (const char            *stream_name,
       if (!g_utf8_validate (*return_location, -1, &end))
         {
           g_free (*return_location);
+          *return_location = NULL;
           g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
                        "Invalid UTF-8 in child %s at offset %lu",
                        stream_name,
@@ -1900,6 +1904,7 @@ g_subprocess_communicate_utf8_finish (GSubprocess   *subprocess,
 {
   gboolean ret = FALSE;
   CommunicateState *state;
+  gchar *local_stdout_buf = NULL, *local_stderr_buf = NULL;
 
   g_return_val_if_fail (G_IS_SUBPROCESS (subprocess), FALSE);
   g_return_val_if_fail (g_task_is_valid (result, subprocess), FALSE);
@@ -1913,11 +1918,11 @@ g_subprocess_communicate_utf8_finish (GSubprocess   *subprocess,
 
   /* TODO - validate UTF-8 while streaming, rather than all at once.
    */
-  if (!communicate_result_validate_utf8 ("stdout", stdout_buf,
+  if (!communicate_result_validate_utf8 ("stdout", &local_stdout_buf,
                                          state->stdout_buf,
                                          error))
     goto out;
-  if (!communicate_result_validate_utf8 ("stderr", stderr_buf,
+  if (!communicate_result_validate_utf8 ("stderr", &local_stderr_buf,
                                          state->stderr_buf,
                                          error))
     goto out;
@@ -1925,5 +1930,14 @@ g_subprocess_communicate_utf8_finish (GSubprocess   *subprocess,
   ret = TRUE;
  out:
   g_object_unref (result);
+
+  if (ret && stdout_buf != NULL)
+    *stdout_buf = g_steal_pointer (&local_stdout_buf);
+  if (ret && stderr_buf != NULL)
+    *stderr_buf = g_steal_pointer (&local_stderr_buf);
+
+  g_free (local_stderr_buf);
+  g_free (local_stdout_buf);
+
   return ret;
 }
diff --git a/gio/tests/gsubprocess-testprog.c b/gio/tests/gsubprocess-testprog.c
index 8d032540c..6794cb375 100644
--- a/gio/tests/gsubprocess-testprog.c
+++ b/gio/tests/gsubprocess-testprog.c
@@ -200,13 +200,18 @@ main (int argc, char **argv)
   GOptionContext *context;
   GError *error = NULL;
   const char *mode;
+  gboolean ret;
 
   context = g_option_context_new ("MODE - Test GSubprocess stuff");
   g_option_context_add_main_entries (context, options, NULL);
-  if (!g_option_context_parse (context, &argc, &argv, &error))
+  ret = g_option_context_parse (context, &argc, &argv, &error);
+  g_option_context_free (context);
+
+  if (!ret)
     {
       g_option_context_free (context);
       g_printerr ("%s: %s\n", argv[0], error->message);
+      g_error_free (error);
       return 1;
     }
 
diff --git a/gio/tests/gsubprocess.c b/gio/tests/gsubprocess.c
index f617bc599..431828384 100644
--- a/gio/tests/gsubprocess.c
+++ b/gio/tests/gsubprocess.c
@@ -1190,7 +1190,7 @@ test_communicate_nothing (void)
 }
 
 static void
-test_communicate_utf8_invalid (void)
+test_communicate_utf8_async_invalid (void)
 {
   GSubprocessFlags flags = G_SUBPROCESS_FLAGS_STDOUT_PIPE;
   GError *error = NULL;
@@ -1222,6 +1222,37 @@ test_communicate_utf8_invalid (void)
   g_object_unref (proc);
 }
 
+/* Test that invalid UTF-8 received using g_subprocess_communicate_utf8()
+ * results in an error. */
+static void
+test_communicate_utf8_invalid (void)
+{
+  GSubprocessFlags flags = G_SUBPROCESS_FLAGS_STDOUT_PIPE;
+  GError *local_error = NULL;
+  gboolean ret;
+  GPtrArray *args;
+  gchar *stdout_str = NULL, *stderr_str = NULL;
+  GSubprocess *proc;
+
+  args = get_test_subprocess_args ("cat", NULL);
+  proc = g_subprocess_newv ((const gchar* const*)args->pdata,
+                            G_SUBPROCESS_FLAGS_STDIN_PIPE | flags,
+                            &local_error);
+  g_assert_no_error (local_error);
+  g_ptr_array_free (args, TRUE);
+
+  ret = g_subprocess_communicate_utf8 (proc, "\xFF\xFF", NULL,
+                                       &stdout_str, &stderr_str, &local_error);
+  g_assert_error (local_error, G_IO_ERROR, G_IO_ERROR_FAILED);
+  g_error_free (local_error);
+  g_assert_false (ret);
+
+  g_assert_null (stdout_str);
+  g_assert_null (stderr_str);
+
+  g_object_unref (proc);
+}
+
 static gboolean
 send_terminate (gpointer   user_data)
 {
@@ -1783,6 +1814,7 @@ main (int argc, char **argv)
       g_free (test_path);
     }
 
+  g_test_add_func ("/gsubprocess/communicate/utf8/async/invalid", test_communicate_utf8_async_invalid);
   g_test_add_func ("/gsubprocess/communicate/utf8/invalid", test_communicate_utf8_invalid);
   g_test_add_func ("/gsubprocess/communicate/nothing", test_communicate_nothing);
   g_test_add_func ("/gsubprocess/terminate", test_terminate);