# XMLUnstructuredGridReader ignores already existing array names in time-series

**URL:** https://discourse.vtk.org/t/xmlunstructuredgridreader-ignores-already-existing-array-names-in-time-series/16414
**Category:** Development
**Tags:** file-formats
**Created:** [May 12, 2026, 9:15am UTC](https://discourse.vtk.org/t/xmlunstructuredgridreader-ignores-already-existing-array-names-in-time-series/16414 "2026-05-12T09:15:28Z")
**Posts on this page:** 1
**Page:** 1

<div class="post-metadata">

### Author: ![jobojeha](https://discourse.vtk.org/user_avatar/discourse.vtk.org/jobojeha/32/10641_2.png) [@jobojeha](https://discourse.vtk.org/u/jobojeha)
#### Post date: [May 12, 2026, 9:15am UTC](https://discourse.vtk.org/t/xmlunstructuredgridreader-ignores-already-existing-array-names-in-time-series/16414/1 "2026-05-12T09:15:28Z")

</div>

I’ve been working with VTK UnstructuredGrid files that contain time series. In your external test files I found [`cube-with-time.vtu`](https://vtk.org/files/ExternalData/SHA512/2fa0dec5c2c558dc49b037f3f1a0e18966e4411ca389bba32990b9ce10c2dbfd406d98da867b3beb3151135c4e990a4c0229aef68ef4b1570bda4e856e7b13dd) which is essentially doing the same thing. Similar to how its described here [Field Data as Time Meta-Data in VTK XML File Formats - VTK documentation](https://docs.vtk.org/en/latest/design_documents/IOXMLTimeInFieldData.html) .

In VTK 9.6 my datasets no longer load any data beyond time step 0. Instead a warning is emitted after reader.Update()

```  
from vtkmodules.vtkIOXML import vtkXMLUnstructuredGridReader  
reader.SetFileName(“cube-with-time.vtu”)  
reader.Update()

2026-05-12 10:23:50.391 ( 32.958s) [D32FF9232C606AC] vtkXMLDataReader.cxx:286 WARN| vtkXMLUnstructuredGridReader (000002314CDB45C0): Another point data array named example data already exists. Ignoring.  
2026-05-12 10:23:50.435 ( 33.002s) [D32FF9232C606AC] vtkXMLDataReader.cxx:286 WARN| vtkXMLUnstructuredGridReader (000002314CDB45C0): Another point data array named example data already exists. Ignoring.  
2026-05-12 10:23:50.435 ( 33.003s) [D32FF9232C606AC] vtkXMLDataReader.cxx:286 WARN| vtkXMLUnstructuredGridReader (000002314CDB45C0): Another point data array named example data already exists. Ignoring.  
2026-05-12 10:23:50.435 ( 33.003s) [D32FF9232C606AC] vtkXMLDataReader.cxx:286 WARN| vtkXMLUnstructuredGridReader (000002314CDB45C0): Another point data array named example data already exists. Ignoring.  
2026-05-12 10:23:50.435 ( 33.003s) [D32FF9232C606AC] vtkXMLDataReader.cxx:286 WARN| vtkXMLUnstructuredGridReader (000002314CDB45C0): Another point data array named example data already exists. Ignoring.  
2026-05-12 10:23:50.435 ( 33.003s) [D32FF9232C606AC] vtkXMLDataReader.cxx:286 WARN| vtkXMLUnstructuredGridReader (000002314CDB45C0): Another point data array named example data already exists. Ignoring.  
2026-05-12 10:23:50.436 ( 33.003s) [D32FF9232C606AC] vtkXMLDataReader.cxx:286 WARN| vtkXMLUnstructuredGridReader (000002314CDB45C0): Another point data array named example data already exists. Ignoring.  
```

On 9.5 this was working perfectly fine and the dataset was accessible for every time step.

On the same note ParaView 6.0.1 can read in cube-with-time.vtu, but 6.1.0 fails with the above warnings. Is this a bug (regression)?

[TestReadXMLUnstructuredGridWithTime.py](https://gitlab.kitware.com/vtk/vtk/-/blob/master/IO/XML/Testing/Python/TestReadXMLUnstructuredGridWithTime.py) also triggers that warning if I run it locally but the assertion still succeeds as the `GetNumberOfTimeSteps` still seems to propagate.