diff --git a/helper/resource/state.go b/helper/resource/state.go
index aafa7f3bc..7473a105e 100644
--- a/helper/resource/state.go
+++ b/helper/resource/state.go
@@ -141,7 +141,7 @@ func (conf *StateChangeConf) WaitForState() (interface{}, error) {
 					}
 				}
 
-				if !found {
+				if !found && len(conf.Pending) > 0 {
 					result.Error = &UnexpectedStateError{
 						LastError:     err,
 						State:         result.State,
diff --git a/helper/resource/state_test.go b/helper/resource/state_test.go
index dcbb3ce67..4b4731351 100644
--- a/helper/resource/state_test.go
+++ b/helper/resource/state_test.go
@@ -70,6 +70,23 @@ func InconsistentStateRefreshFunc() StateRefreshFunc {
 	}
 }
 
+func UnknownPendingStateRefreshFunc() StateRefreshFunc {
+	sequence := []string{
+		"unknown1", "unknown2", "done",
+	}
+
+	r := NewStateGenerator(sequence)
+
+	return func() (interface{}, string, error) {
+		idx, s, err := r.NextState()
+		if err != nil {
+			return nil, "", err
+		}
+
+		return idx, s, nil
+	}
+}
+
 func TestWaitForState_inconsistent_positive(t *testing.T) {
 	conf := &StateChangeConf{
 		Pending:                   []string{"replicating"},
@@ -154,6 +171,22 @@ func TestWaitForState_success(t *testing.T) {
 	}
 }
 
+func TestWaitForState_successUnknownPending(t *testing.T) {
+	conf := &StateChangeConf{
+		Target:  []string{"done"},
+		Refresh: UnknownPendingStateRefreshFunc(),
+		Timeout: 200 * time.Second,
+	}
+
+	obj, err := conf.WaitForState()
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+	if obj == nil {
+		t.Fatalf("should return obj")
+	}
+}
+
 func TestWaitForState_successEmpty(t *testing.T) {
 	conf := &StateChangeConf{
 		Pending: []string{"pending", "incomplete"},