diff --git a/nifty5/operators/mask_operator.py b/nifty5/operators/mask_operator.py
index 0ff519fbc6aed7b5d99b1830b874277bab683891..ef61ac2502f8b53e8bd411eefce6a059f2743551 100644
--- a/nifty5/operators/mask_operator.py
+++ b/nifty5/operators/mask_operator.py
@@ -34,18 +34,21 @@ class MaskOperator(LinearOperator):
         self._target = DomainTuple.make(UnstructuredDomain(self._mask.sum()))
 
     def data_indices(self):
-        return np.indices(self.domain.shape).transpose((1, 2, 0))[self._mask]
+        if len(self.domain.shape) == 1:
+            return np.arange(self.domain.shape[0])[self._mask]
+        if len(self.domain.shape) == 2:
+            return np.indices(self.domain.shape).transpose((1, 2, 0))[self._mask]
 
     def apply(self, x, mode):
         self._check_input(x, mode)
         if mode == self.TIMES:
             res = x.to_global_data()[self._mask]
-            return Field(self.target, res)
+            return Field.from_global_data(self.target, res)
         x = x.to_global_data()
         res = np.empty(self.domain.shape, x.dtype)
         res[self._mask] = x
         res[~self._mask] = 0
-        return Field(self.domain, res)
+        return Field.from_global_data(self.domain, res)
 
     @property
     def capability(self):
diff --git a/test/test_operators/test_adjoint.py b/test/test_operators/test_adjoint.py
index 13fd6650473665a2efe76c75adc52098f9073799..9df172961406ce7b825b375ab020083a679d5132 100644
--- a/test/test_operators/test_adjoint.py
+++ b/test/test_operators/test_adjoint.py
@@ -64,10 +64,10 @@ class Consistency_Tests(unittest.TestCase):
     @expand(product(_p_spaces, [np.float64, np.complex128]))
     def testMask(self, sp, dtype):
         # Create mask
-        f = ift.from_random('normal', sp).val
+        f = ift.from_random('normal', sp).to_global_data()
         mask = np.zeros_like(f)
         mask[f > 0] = 1
-        mask = ift.Field(sp, mask)
+        mask = ift.Field.from_global_data(sp, mask)
         # Test MaskOperator
         op = ift.MaskOperator(mask)
         ift.extra.consistency_check(op, dtype, dtype)