# problem reading large VTU file
**URL:** https://discourse.paraview.org/t/problem-reading-large-vtu-file/6887
**Category:** ParaView Support
**Created:** [April 7, 2021, 8:25am UTC](https://discourse.paraview.org/t/problem-reading-large-vtu-file/6887 "2021-04-07T08:25:39Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@Ehsan\_Izadi](https://discourse.paraview.org/u/Ehsan_Izadi)
#### Post date: [April 7, 2021, 8:25am UTC](https://discourse.paraview.org/t/problem-reading-large-vtu-file/6887/1 "2021-04-07T08:25:39Z")
Hi,
I am having issues reading a large vtu file. I have tried various versions of Paraview on Windows and Ubuntu, but the problem is persistent. The VTU file consist of 404000 unstructured data points and when I try to load it, paraview says:
> ERROR: In /build/paraview-vlxewD/paraview-5.7.0/VTK/IO/XML/vtkXMLUnstructuredDataReader.cxx, line 601 vtkXMLUnstructuredGridReader (0x560f46d55990): Cannot read cell offsets from Cells in piece 0 because the “offsets” array is not long enough.
I was wondering if this is a bug. Any help?
I have uploaded the VTU file here: [https://drive.google.com/file/d/1SLBgip9\_pkEO3hd1BzN98\_Y078fITU8X/view?usp=sharing](https://drive.google.com/file/d/1SLBgip9_pkEO3hd1BzN98_Y078fITU8X/view?usp=sharing)
Thanks in advance.
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [April 7, 2021, 8:30am UTC](https://discourse.paraview.org/t/problem-reading-large-vtu-file/6887/2 "2021-04-07T08:30:28Z")
How was this file generated ?
Many arrays contains actual ` ***** ` instead of values, which is invalid.
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### Author:  [@Ehsan\_Izadi](https://discourse.paraview.org/u/Ehsan_Izadi)
#### Post date: [April 7, 2021, 8:48am UTC](https://discourse.paraview.org/t/problem-reading-large-vtu-file/6887/3 "2021-04-07T08:48:52Z")
Thanks for your answer. But this is not the source of the issue. When I manually change the \*\* values to “0”, it gives me the same error.
I found the same issue also in CFD forums: [Problem opening vtu-file in Paraview -- CFD Online Discussion Forums](https://www.cfd-online.com/Forums/su2/227916-problem-opening-vtu-file-paraview.html)
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [April 7, 2021, 8:51am UTC](https://discourse.paraview.org/t/problem-reading-large-vtu-file/6887/4 "2021-04-07T08:51:54Z")
> [@mwestphal](#):
>
> How was this file generated ?
How was this file generated ?
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### Author:  [@Ehsan\_Izadi](https://discourse.paraview.org/u/Ehsan_Izadi)
#### Post date: [April 7, 2021, 9:11am UTC](https://discourse.paraview.org/t/problem-reading-large-vtu-file/6887/5 "2021-04-07T09:11:26Z")
Oops! sorry, I forgot to answer this question.
The file is generated by a Fortran code (as a part of a software). But when the number of data points in VTU is smaller (maybe up to 100000) it works fine. However, when the number of data points exceeds a certain value, then it becomes unreadable by Paraview.