# error e0400b
**URL:** https://community.pix4d.com/t/error-e0400b/4333
**Category:** PIX4Dmapper Questions/Troubleshooting
**Created:** [December 21, 2017, 12:18pm UTC](https://community.pix4d.com/t/error-e0400b/4333 "2017-12-21T12:18:21Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@Geo\_Info](https://community.pix4d.com/u/Geo_Info)
#### Post date: [December 21, 2017, 12:18pm UTC](https://community.pix4d.com/t/error-e0400b/4333/1 "2017-12-21T12:18:21Z")
Hi,
I’m getting this error “error e0400b”, i’ve tried to install the previous version and open them but the projects i’ve tried to open can not be opened…it says that it’s created by a higher version.
At this point it’s not really a problem if this problem will be solved in another (higher) version.
Regards
Stanley
---
### Author:  [@Selim\_Erguden](https://community.pix4d.com/u/Selim_Erguden)
#### Post date: [December 21, 2017, 3:00pm UTC](https://community.pix4d.com/t/error-e0400b/4333/2 "2017-12-21T15:00:39Z")
Hey Geo Info,
If your project is created using a higher version of Pix4d, there is a way to downgrade the version using Notepad ++ for the .pd file. Make sure you make a second copy of your .p4d file just in case. Then you need to edit the _p4dVersion_ in the .p4d file using Notepad ++ and, the _p4dVersion_ needs to be set to 10.
---
### Author:  [@Geo\_Info](https://community.pix4d.com/u/Geo_Info)
#### Post date: [December 22, 2017, 8:50am UTC](https://community.pix4d.com/t/error-e0400b/4333/3 "2017-12-22T08:50:47Z")
Hi Selim,
Thanx for your comment.
I will download Notepad ++ and try it.
---
### Author:  [@Marili\_Giovani](https://community.pix4d.com/u/Marili_Giovani)
#### Post date: [December 22, 2017, 12:23pm UTC](https://community.pix4d.com/t/error-e0400b/4333/4 "2017-12-22T12:23:32Z")
Hello,
This error might occur with projects that were created with different versions, as Selim said.
When opening a project that was created with a very old version, you should gradually open it with the in-between versions to convert the file to the latest format.
---
### Author:  [@Geo\_Info](https://community.pix4d.com/u/Geo_Info)
#### Post date: [December 22, 2017, 1:16pm UTC](https://community.pix4d.com/t/error-e0400b/4333/5 "2017-12-22T13:16:44Z")
Hi,
Ok, i think i understand.
So the best way is with every upgrade to open every project to be sure it will work in the next version…??
I have more then 40 projects and still growing (fast)…
Maybe it’s an idea to make this easier in the next versions?
thanx
---
### Author:  [@pixmap\_operations](https://community.pix4d.com/u/pixmap_operations)
#### Post date: [December 22, 2017, 1:36pm UTC](https://community.pix4d.com/t/error-e0400b/4333/6 "2017-12-22T13:36:05Z")
I seem to have the same problem. As I try to open projects created with Pix4Dmapper 4.0.24 (not a very old version) I always get this error together with the following log output:
```
[Processing]: ProjectLoading
[Error]: XML file validation failed with XSD: C:/Program Files/Pix4Dmapper/resources/xsd/17/pix4d.xsd
[Error]: Error e0400b: Cannot open project E:\pixmap\projects\p376\processing\p376.p4d. Invalid format.
```
I tried 4 different projects, no way.
Reto
---
### Author:  [@Marili\_Giovani](https://community.pix4d.com/u/Marili_Giovani)
#### Post date: [December 22, 2017, 1:50pm UTC](https://community.pix4d.com/t/error-e0400b/4333/7 "2017-12-22T13:50:43Z")
Hello again,
For the case of Stanley, he shared the .p4d files with us and here is the workflow:
1. Right click the .p4d file and click _Edit with Notepad ++._
2.change the OptimizerType from \_Classic \_to \_Ceres \_in line 35 so that it appears as below:
* * *
\
\Ceres\
* * *
1. Save the .p4d file and open the project again.
This error occured because of the change in the calibration algorithm.
I hope it works for you too Reto.
---
### Author:  [@Geo\_Info](https://community.pix4d.com/u/Geo_Info)
#### Post date: [December 22, 2017, 2:02pm UTC](https://community.pix4d.com/t/error-e0400b/4333/8 "2017-12-22T14:02:54Z")
Hi Reto
At first i renamed the newversion.p4d that didn’t work out.
Then i renamed the Original one and named the newversion.p4d as the original.
And it worked!!
---
### Author:  [@pixmap\_operations](https://community.pix4d.com/u/pixmap_operations)
#### Post date: [December 22, 2017, 2:33pm UTC](https://community.pix4d.com/t/error-e0400b/4333/9 "2017-12-22T14:33:43Z")
I changed the optimizer type from Classic to Ceres and it worked.
Thank you, Marili, you saved my day 🙂
---
### Author:  [@David\_Schlosser](https://community.pix4d.com/u/David_Schlosser)
#### Post date: [February 8, 2018, 4:05pm UTC](https://community.pix4d.com/t/error-e0400b/4333/10 "2018-02-08T16:05:38Z")
Hello,
I am having a similar issue with getting an
“XML file validation failed with XSD: C:/Program Files/Pix4Dmapper/resources/xsd/17/pix4d.xsd” error.
Currently, I am trying to create a new project by merging to other projects (one processed with the most up to date version, and one from the previous version). I checked the file using Notepad++, and it looks like both are set to “CERES”.
I can try the successive opening in the file with older version since it is only one version below the current.
Is there something else I can try to fix this issue?
---
### Author:  [@Marili\_Giovani](https://community.pix4d.com/u/Marili_Giovani)
#### Post date: [February 9, 2018, 2:34pm UTC](https://community.pix4d.com/t/error-e0400b/4333/11 "2018-02-09T14:34:30Z")
Hello David,
Can you please send us the .p4d file?
- Which version did you use to create the project?
- Which version do you have installed on your computer at that moment?
---
### Author:  [@David\_Schlosser](https://community.pix4d.com/u/David_Schlosser)
#### Post date: [February 9, 2018, 4:58pm UTC](https://community.pix4d.com/t/error-e0400b/4333/12 "2018-02-09T16:58:23Z")
Marili,
One project was created using 4.1.24, and the other using 4.1.5. Currently, I have Version 4.1.24 (the newest one?) installed.
I will send both files.
Thank you!
-David
---
### Author:  [@JS\_S](https://community.pix4d.com/u/JS_S)
#### Post date: [January 7, 2019, 8:45am UTC](https://community.pix4d.com/t/error-e0400b/4333/13 "2019-01-07T08:45:22Z")
I’m using Pix4d version 3.3.29. Yes its old. Can’t upgrade the software as per T&C of my educational package.
However, whatever project I have worked on is unable to be opened by the Pix4d software even after immediate completion of processing. Kindly assist
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### Author:  [@Pix4D\_Alumni\_MV](https://community.pix4d.com/u/Pix4D_Alumni_MV)
#### Post date: [January 7, 2019, 1:57pm UTC](https://community.pix4d.com/t/error-e0400b/4333/14 "2019-01-07T13:57:00Z")
Hi JS S,
Could you give us more information on your issue? (Screenshots for example)
It means that you are able to process your project and then you are not able to open your projects anymore?
Maybe uninstall and reinstall could do the trick. We can provide us a download link for this version if needed.
We just want to understand what is going on.
Thanks,
Best,
---
### Author:  [@JS\_S](https://community.pix4d.com/u/JS_S)
#### Post date: [January 8, 2019, 3:21pm UTC](https://community.pix4d.com/t/error-e0400b/4333/15 "2019-01-08T15:21:23Z")
Hi, yes I am able to process a project but unable to open the project anymore. Please see the screenshot below. If you suggest reinstalling the software kindly provide the link for the same version. TQ
---
### Author:  [@Pix4D\_Alumni\_MV](https://community.pix4d.com/u/Pix4D_Alumni_MV)
#### Post date: [January 9, 2019, 12:38pm UTC](https://community.pix4d.com/t/error-e0400b/4333/16 "2019-01-09T12:38:16Z")
Hi JS S,
Have you tried the solution described above?
It is described here as well.
[XML file validation failed with XSD and e0400b](https://community.pix4d.com/t/4224)
Basically, I have opened the .p4d file using a text editor (notepad ++)
and I replaced the Optimizer type from \_Classic \_to \_Ceres \_as you will see in the screenshot below.
If it does not do the trick, you can download the Pix4Dmapper 3.3.29 [here.](https://drive.google.com/open?id=1uBdnYA1J-a6mgADCZ83u48DBFj1F8iss)
Please note that older versions of our software might still hold some of your personal data. However even if you’re using an older version of our software, you can still let us know how to handle your data. Learn more and update your preferences now. More information here: [https://pix4d.com/pix4d-and-the-gdpr/](https://pix4d.com/pix4d-and-the-gdpr/).
Best,
---
### Author:  [@Mitch\_Cavanaugh](https://community.pix4d.com/u/Mitch_Cavanaugh)
#### Post date: [July 13, 2021, 5:03pm UTC](https://community.pix4d.com/t/error-e0400b/4333/17 "2021-07-13T17:03:10Z")
I’m having this issue after a crash. Other files open, but the one I was working in keeps sending this error. I’ve tried The Notebook++ route without luck.
[9929 Fairfield2.p4d](https://community.pix4d.com/uploads/short-url/xmdQu0vd4boAq8nhUJIEAvKUWSe.p4d) (341.7 KB)
---
### Author:  [@Yuka](https://community.pix4d.com/u/Yuka)
#### Post date: [July 14, 2021, 7:10am UTC](https://community.pix4d.com/t/error-e0400b/4333/18 "2021-07-14T07:10:27Z")
Unfortunately, I was not able to read the file you attached. The project file could be broken which could be the reason why you cannot open it. Would you please reprocess it and see if it works?
Kind regards,
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### Author:  [@Mitch\_Cavanaugh](https://community.pix4d.com/u/Mitch_Cavanaugh)
#### Post date: [July 14, 2021, 7:10pm UTC](https://community.pix4d.com/t/error-e0400b/4333/19 "2021-07-14T19:10:44Z")
I’m unable to open the file at all, so I don’t know how I’d process it. Sorry, still new to Pix4D.
---
### Author:  [@Yuka](https://community.pix4d.com/u/Yuka)
#### Post date: [July 15, 2021, 6:48am UTC](https://community.pix4d.com/t/error-e0400b/4333/20 "2021-07-15T06:48:09Z")
You may have to create a new project importing the images. There is a video explaining the steps as well as the document:
> **[New project in PIX4Dmapper](https://support.pix4d.com/hc/en-us/articles/115002472026-New-project-in-Pix4Dmapper)**
>
> Previous | Next
>
>
>
> This section goes step by step through the process of creating a new project. Example image datasets can be downloaded from the Example projects.
>
> Creating a new project
> To c...
Hope it helps.