# Getting "Byte order could not be determined" error when opening up Ensight Case Gold files written from ANSYS Fluent 2021R2
**URL:** https://discourse.paraview.org/t/getting-byte-order-could-not-be-determined-error-when-opening-up-ensight-case-gold-files-written-from-ansys-fluent-2021r2/12250
**Category:** ParaView Support
**Tags:** mpi, python, vtk
**Created:** [June 7, 2023, 5:54pm UTC](https://discourse.paraview.org/t/getting-byte-order-could-not-be-determined-error-when-opening-up-ensight-case-gold-files-written-from-ansys-fluent-2021r2/12250 "2023-06-07T17:54:07Z")
**Posts on this page:** 19
**Page:** 1
### Author:  [@austinbenny](https://discourse.paraview.org/u/austinbenny)
#### Post date: [June 7, 2023, 5:54pm UTC](https://discourse.paraview.org/t/getting-byte-order-could-not-be-determined-error-when-opening-up-ensight-case-gold-files-written-from-ansys-fluent-2021r2/12250/1 "2023-06-07T17:54:07Z")
My workflow is to have ANSYS Fluent 2021R2 write **Ensight Case Gold** files that i then post-process in paraview. I could successfully do this before with a different simulation (the ANSYS Fluent version and paraview version are remained the same), but for some reason, when i try to open my \*.case file with this simulation, Paraview 5.10.1 spits out this error.
I am running a parallelized version of paraview but this error is also given when i run paraview on a single core. After doing some digging online, several people have encountered this issue. I have also applied the fixes to the encase/case file described in [this](https://discourse.paraview.org/t/fluent-2021-r1-ensight-case-gold-solution-files-to-paraview-5-9-0/7512/4) thread.
```auto
ERROR: In /builds/gitlab-kitware-sciviz-ci/build/superbuild/paraview/src/VTKExtensions/IOEnSight/vtkPEnSightGoldBinaryReader.cxx, line 4159
vtkPEnSightGoldBinaryReader (0x1dd4610): Byte order could not be determined.
ERROR: In /builds/gitlab-kitware-sciviz-ci/build/superbuild/paraview/src/VTKExtensions/IOEnSight/vtkPEnSightGoldBinaryReader.cxx, line 332
vtkPEnSightGoldBinaryReader (0x1dd4610): Invalid part id; check that ByteOrder is set correctly.
ERROR: In /builds/gitlab-kitware-sciviz-ci/build/superbuild/paraview/src/VTKExtensions/IOEnSight/vtkPEnSightReader.cxx, line 341
vtkPEnSightGoldBinaryReader (0x1dd4610): error reading geometry file lower_iha_primary_case.geo 0
ERROR: In /builds/gitlab-kitware-sciviz-ci/build/superbuild/paraview/src/VTK/Common/ExecutionModel/vtkExecutive.cxx, line 753
vtkCompositeDataPipeline (0x17606b90): Algorithm vtkPEnSightGoldBinaryReader(0x1dd4610) returned failure for request: vtkInformation (0x1761adb0)
Debug: Off
Modified Time: 165820
Reference Count: 1
Registered Events: (none)
Request: REQUEST_DATA
FROM_OUTPUT_PORT: 0
ALGORITHM_AFTER_FORWARD: 1
FORWARD_DIRECTION: 0
```
If i write the same Ensight file but in ASCII (as is an option that ANSYS Fluent provides), i can successfully open it. I prefer the file in binary because it’s smaller and will potentially open up faster.
EDIT: This issue also seems to be captured [here](https://www.cfd-online.com/Forums/paraview/130739-ensight-byte-order.html).
---
### Author:  [@BECTOn](https://discourse.paraview.org/u/BECTOn)
#### Post date: [November 16, 2023, 10:33am UTC](https://discourse.paraview.org/t/getting-byte-order-could-not-be-determined-error-when-opening-up-ensight-case-gold-files-written-from-ansys-fluent-2021r2/12250/2 "2023-11-16T10:33:17Z")
Hi there,
the same issue over here. I followed the recommended procedure with Ensight-Gold Format for two simple and small cases and it worked OK. However, when I attempted to import results of a larger Steady-State CHT analysis I encountered the same issues.
Error message from Paraview 5.9.1.:
```auto
ERROR: In C:\glr\builds\paraview\paraview-ci\build\superbuild\paraview\src\VTK\IO\EnSight\vtkEnSightGoldBinaryReader.cxx, line 4324
vtkEnSightGoldBinaryReader (000001E834CE7190): Byte order could not be determined.
ERROR: In C:\glr\builds\paraview\paraview-ci\build\superbuild\paraview\src\VTK\IO\EnSight\vtkEnSightGoldBinaryReader.cxx, line 348
vtkEnSightGoldBinaryReader (000001E834CE7190): Invalid part id; check that ByteOrder is set correctly.
ERROR: In C:\glr\builds\paraview\paraview-ci\build\superbuild\paraview\src\VTK\IO\EnSight\vtkEnSightReader.cxx, line 297
vtkEnSightGoldBinaryReader (000001E834CE7190): error reading geometry file
ERROR: In C:\glr\builds\paraview\paraview-ci\build\superbuild\paraview\src\VTK\Common\ExecutionModel\vtkExecutive.cxx, line 753
vtkCompositeDataPipeline (000001E8336968A0): Algorithm vtkEnSightGoldBinaryReader(000001E834CE7190) returned failure for request: vtkInformation (000001E831BC89C0)
Debug: Off
Modified Time: 1925643
Reference Count: 1
Registered Events: (none)
Request: REQUEST_DATA
FORWARD_DIRECTION: 0
FROM_OUTPUT_PORT: 0
ALGORITHM_AFTER_FORWARD: 1
```
Error message from ParaView 5.11.2:
```auto
ERROR: In vtkEnSightGoldBinaryReader.cxx, line 3314
vtkEnSightGoldBinaryReader (000001EDD79CD8A0): Byte order could not be determined.
ERROR: In vtkEnSightGoldBinaryReader.cxx, line 490
vtkEnSightGoldBinaryReader (000001EDD79CD8A0): Invalid part id; check that ByteOrder is set correctly.
ERROR: In vtkEnSightReader.cxx, line 297
vtkEnSightGoldBinaryReader (000001EDD79CD8A0): error reading geometry file
ERROR: In vtkExecutive.cxx, line 741
vtkCompositeDataPipeline (000001EDD77AB100): Algorithm vtkEnSightGoldBinaryReader (000001EDD79CD8A0) returned failure for request: vtkInformation (000001EDE6D73D70)
Debug: Off
Modified Time: 462415
Reference Count: 1
Registered Events: (none)
Request: REQUEST_DATA
FORWARD_DIRECTION: 0
ALGORITHM_AFTER_FORWARD: 1
FROM_OUTPUT_PORT: 0
```
Any suggestions are welcome. Thanks.
---
### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [November 16, 2023, 12:26pm UTC](https://discourse.paraview.org/t/getting-byte-order-could-not-be-determined-error-when-opening-up-ensight-case-gold-files-written-from-ansys-fluent-2021r2/12250/3 "2023-11-16T12:26:26Z")
please share your data
---
### Author:  [@ludovica](https://discourse.paraview.org/u/ludovica)
#### Post date: [June 25, 2024, 9:12am UTC](https://discourse.paraview.org/t/getting-byte-order-could-not-be-determined-error-when-opening-up-ensight-case-gold-files-written-from-ansys-fluent-2021r2/12250/4 "2024-06-25T09:12:07Z")
I have the same problem, any help? Here it is my .case file
[Q\_1-11.case](https://discourse.paraview.org/uploads/short-url/69KXkSn9RStg83gsspUXA797e.case) (3.4 KB)
I have already modified my file by removing any quotes and by removing the last two line.
---
### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [June 25, 2024, 9:16am UTC](https://discourse.paraview.org/t/getting-byte-order-could-not-be-determined-error-when-opening-up-ensight-case-gold-files-written-from-ansys-fluent-2021r2/12250/5 "2024-06-25T09:16:43Z")
please share the .geo file as well.
---
### Author:  [@ludovica](https://discourse.paraview.org/u/ludovica)
#### Post date: [June 25, 2024, 9:24am UTC](https://discourse.paraview.org/t/getting-byte-order-could-not-be-determined-error-when-opening-up-ensight-case-gold-files-written-from-ansys-fluent-2021r2/12250/6 "2024-06-25T09:24:18Z")
Here it is, thanks for your quick response. It was too large that I had to share it with drive
> **[Google Drive: Sign-in](https://accounts.google.com/v3/signin/identifier?continue=https%3A%2F%2Fdrive.google.com%2Ffile%2Fd%2F1zt1aYiyNrguQ8QXanmWDOullW-c7ZfKm%2Fview%3Fusp%3Ddrive_link&followup=https%3A%2F%2Fdrive.google.com%2Ffile%2Fd%2F1zt1aYiyNrguQ8QXanmWDOullW-c7ZfKm%2Fview%3Fusp%3Ddrive_link&ifkv=AS5LTATWSgwKyKx7sypEmmQw0FxjjseBLudXI3PFS5TTvwfZs5F6wz_FdmqDysGtgAdoK5XewXERjg&osid=1&passive=1209600&service=wise&flowName=GlifWebSignIn&flowEntry=ServiceLogin&dsh=S-2029703024%3A1719307450950501&ddm=0)**
>
> Access Google Drive with a Google account (for personal use) or Google Workspace account (for business use).
---
### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [June 25, 2024, 9:52am UTC](https://discourse.paraview.org/t/getting-byte-order-could-not-be-determined-error-when-opening-up-ensight-case-gold-files-written-from-ansys-fluent-2021r2/12250/7 "2024-06-25T09:52:17Z")
I’ve requested access.
---
### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [June 25, 2024, 9:59am UTC](https://discourse.paraview.org/t/getting-byte-order-could-not-be-determined-error-when-opening-up-ensight-case-gold-files-written-from-ansys-fluent-2021r2/12250/8 "2024-06-25T09:59:41Z")
I confirm the issue:
```auto
( 19.744s) [paraview]vtkEnSightGoldBinaryRea:3321 ERR| vtkEnSightGoldBinaryReader (0x57825b5c9940): Byte order could not be determined.
( 19.757s) [paraview]vtkEnSightGoldBinaryRea:490 ERR| vtkEnSightGoldBinaryReader (0x57825b5c9940): Invalid part id; check that ByteOrder is set correctly.
( 19.757s) [paraview] vtkEnSightReader.cxx:292 ERR| vtkEnSightGoldBinaryReader (0x57825b5c9940): error reading geometry file
( 19.757s) [paraview] vtkExecutive.cxx:729 ERR| vtkCompositeDataPipeline (0x57825f202380): Algorithm vtkEnSightGoldBinaryReader (0x57825b5c9940) returned failure for request: vtkInformation (0x5782602f65e0)
Debug: Off
Modified Time: 467583
Reference Count: 1
Registered Events: (none)
Request: REQUEST_DATA
FROM_OUTPUT_PORT: 0
ALGORITHM_AFTER_FORWARD: 1
FORWARD_DIRECTION: 0
```
However without investigation it is hard to say if this is an issue with your file or with the ensight reader
---
### Author:  [@ludovica](https://discourse.paraview.org/u/ludovica)
#### Post date: [June 25, 2024, 10:22am UTC](https://discourse.paraview.org/t/getting-byte-order-could-not-be-determined-error-when-opening-up-ensight-case-gold-files-written-from-ansys-fluent-2021r2/12250/9 "2024-06-25T10:22:32Z")
The only thing I can say is that these files come from Ansys Fluent and I did 2 different extrapolation of encase gold file:
-The first one: I did the simulation in Fluent and after the calculation i went to File-\>Export-\> Solution Data…, in the window that opens after selecting solution data i select File Type:EnSight Case Gold, Location:Node, Format: ASCII. With this routine I obtained .case, .geo, .scl, .vel, ecc. and if I load the .case file in paraview there is no problem in the load.
-The second one: Before doing the simulation I went to File-\>Export-\>During Calculation-\>Solution Data… and in the window that opens I selected the same as before. With this routine I obtain the same files but these are referred to each time steps.
So, where could be the problem? Why the .case file is read in the first case and not in the second one? When I load the .case file I have to select something else beacuse the .case is referred to each time steps?
Thanks anyway
---
### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [June 25, 2024, 10:51am UTC](https://discourse.paraview.org/t/getting-byte-order-could-not-be-determined-error-when-opening-up-ensight-case-gold-files-written-from-ansys-fluent-2021r2/12250/10 "2024-06-25T10:51:42Z")
> [@ludovica](#):
>
> Why the .case file is read in the first case and not in the second one?
First is ASCII, second is binary.
---
### Author:  [@ludovica](https://discourse.paraview.org/u/ludovica)
#### Post date: [June 25, 2024, 10:56am UTC](https://discourse.paraview.org/t/getting-byte-order-could-not-be-determined-error-when-opening-up-ensight-case-gold-files-written-from-ansys-fluent-2021r2/12250/11 "2024-06-25T10:56:19Z")
It is binary even if I choose Format ASCII? (I can choose it in the second routine too)
---
### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [June 25, 2024, 10:56am UTC](https://discourse.paraview.org/t/getting-byte-order-could-not-be-determined-error-when-opening-up-ensight-case-gold-files-written-from-ansys-fluent-2021r2/12250/12 "2024-06-25T10:56:48Z")
Ha, I missed that.
I’m afraid I do not know and more investigation is needed.
---
### Author:  [@ludovica](https://discourse.paraview.org/u/ludovica)
#### Post date: [June 25, 2024, 10:59am UTC](https://discourse.paraview.org/t/getting-byte-order-could-not-be-determined-error-when-opening-up-ensight-case-gold-files-written-from-ansys-fluent-2021r2/12250/13 "2024-06-25T10:59:50Z")
Thank you very much, I appreciate.
---
### Author:  [@nabla](https://discourse.paraview.org/u/nabla)
#### Post date: [October 9, 2024, 7:57am UTC](https://discourse.paraview.org/t/getting-byte-order-could-not-be-determined-error-when-opening-up-ensight-case-gold-files-written-from-ansys-fluent-2021r2/12250/14 "2024-10-09T07:57:09Z")
Hi!
I’m facing the same issue, is there any update on this since it was flagged?
---
### Author:  [@nabla](https://discourse.paraview.org/u/nabla)
#### Post date: [December 9, 2024, 10:56am UTC](https://discourse.paraview.org/t/getting-byte-order-could-not-be-determined-error-when-opening-up-ensight-case-gold-files-written-from-ansys-fluent-2021r2/12250/15 "2024-12-09T10:56:09Z")
@mwestphal, are you aware of any progress on this problem? Judging from this forum and others, it seems a fairly common issue that would be worth addressing.
---
### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [December 9, 2024, 11:01am UTC](https://discourse.paraview.org/t/getting-byte-order-could-not-be-determined-error-when-opening-up-ensight-case-gold-files-written-from-ansys-fluent-2021r2/12250/16 "2024-12-09T11:01:51Z")
Definitely ! I agree!
However, this will requires some contribution, either from a dev spending some time or from a someone funding the issue.
Do not hesitate to reach out to Kitware if you are interested by that.
[https://www.kitware.com/](https://www.kitware.com/)
[https://discourse.paraview.org/t/how-are-features-and-bug-fixes-incorporated-into-paraview/4735/3](https://discourse.paraview.org/t/how-are-features-and-bug-fixes-incorporated-into-paraview/4735/3)
---
### Author:  [@Trupenparikh](https://discourse.paraview.org/u/Trupenparikh)
#### Post date: [December 9, 2025, 11:20am UTC](https://discourse.paraview.org/t/getting-byte-order-could-not-be-determined-error-when-opening-up-ensight-case-gold-files-written-from-ansys-fluent-2021r2/12250/17 "2025-12-09T11:20:21Z")
I just found out the solution. For someone that are still facing the issue can try this.
So I just found out that Ensight case gold files cannot handle part id above 65000. I had a part id of 85091. This part ID can be seen in ANSYS Fluent. Each zone and boundary has an ID that can be seen in Fluent boundary conditions and zone conditions tree. The ID is just beside the name of the zone or boundary. You will need to change this ID for each zone and boundary that has a value above 65000. This can be done using the following command in Fluent TUI.
(set-thread-id (%get-thread-by-id old-id) new-id)
e.g. - (set-thread-id (%get-thread-by-id 85091) 1)
After this is done, export the binary ensight case gold file and than you should be able to open it in Paraview.
---
### Author:  [@tpalloj](https://discourse.paraview.org/u/tpalloj)
#### Post date: [February 25, 2026, 8:22pm UTC](https://discourse.paraview.org/t/getting-byte-order-could-not-be-determined-error-when-opening-up-ensight-case-gold-files-written-from-ansys-fluent-2021r2/12250/18 "2026-02-25T20:22:36Z")
This fixed the issue for me as well. I have been looking for a way around this for a while - thanks!
Is there a way to have Fluent auto-assign smaller PIDs so we don’t have to repeat this in the future? Or have you found a cleaner workaround to rename them?
---
### Author:  [@Trupenparikh](https://discourse.paraview.org/u/Trupenparikh)
#### Post date: [July 29, 2026, 8:50am UTC](https://discourse.paraview.org/t/getting-byte-order-could-not-be-determined-error-when-opening-up-ensight-case-gold-files-written-from-ansys-fluent-2021r2/12250/19 "2026-07-29T08:50:07Z")
Sorry for the late reply. I haven’t found a way to auto assign PID. I will update here if I find it.