Error e0400e


I have a problem with converting an old Pix4D file to use with the current release of Pix4D. The original file is from version 2.0.89 and I am using version 4.1.19.

I read in the troubleshooting that I have to open the file gradually with other versions of the software, but this means I have to mess up my Pix4D installation seriously.

I get the error e0400e and the following text:

[Error]: XML file validation failed with XSD: C:/Program Files/Pix4Dmapper/resources/xsd/0/pix4d.xsd

[Error]: Failure converting p4d file [D:/Pix4D/vaia-nov.p4d] to [D:/Pix4D/va.p4d]

[Error]: Error e0400e: Cannot open project D:/Pix4D/va.p4d. Cannot convert the project file to the latest format.

After that, when I open the converted file, Pix4D says it needs to be converted, but shows it is the same version. I tried opening with Notepad++ and the converted file looks the same as the original one. Also, there is no Optimizer - Ceres on line 35.

After this, I open the "converted"file again, Pix4D prompts for further conversion, I do it and then the result is the same Error e0400e, but the resulting Pix4D file is significantly smaller - 8KB for example.

This project I am converting is very important to me, could you give me some instructions to converting it?

Here are the links to my Pix4D files:



Converted twice

Thanks in advance,


*** UPDATE : I tried downloading every version of Pix4D from this thread, but even with 2.2.26 it does not work. I tried all the later ones, but no success… The project is quite large and processing it again would cost me a lot of time. Please advise!


Hey Veska,

Have you tried you editing the p4dVersion  in the .p4d file using Notepad ++ and changing the p4dVersion  set to 10? 


Has there been any updates regarding opening old .p4d files with later versions of the software? We have an old job created in 2.0.104 which we are wanting to open now with our current version 4.0.25. Is there any easy way to achieve this without having to download old versions of Pix4d and go through an incremental opening process with successive versions of the software?

Seems to me that there is a bug in version 4.1.24


I can’t open any older projects (from 4.0.25) with version 4.1.24



@Veska and @Darren

The jump between versions is too great (2.0 to 4.1), so even manually editing the .p4d file probably will not work, because too many things have changed in its content. This is why we always recommend no to wait too long before upgrading.

I have followed-up with you via our ticketing system.


@ Derrick

Some projects that were created or opened with version 4.0 did not have their project file (.p4d) formatted correctly. As a consequence, these projects cannot be opened using version 4.1. To be able to load the projects again, please proceed as follows:

  1. Open this file located in the Pix4Dmapper installation folder _C:\Program Files\Pix4Dmapper\resources\xsl\16_ pix4d.xsl  with a text editor like Notepad++.
  2. Find the line <xsl:template match=“/pix4dmapper/initial/optimizerType”>.
  3. Replace it with <xsl:template match=“/pix4dmapper/ options /initial/optimizerType”>.
  4. Save and close the file.

Note that this allows you to open .p4d files using 4.1 only if they were not opened before using 4.1. In other words, if a .p4d file was tried to be opened, the .p4d file became corrupted. It is then needed to “reset” the .p4d file using a text editor (Notepad++) as below:

To sum up:

  • Editing the  pix4d.xsl  in the installation folder of Pix4Dmapper is required.
  • For .p4d files that you already tried to open with 4.1, ensure they comply with the screenshot above.
  • For .p4d files that were not opened with 4.1 yet, no need to do anything.


I hope this helps!



Thank you for posting that.  I just went through your instructions and was able to open my 4.0.25 projects after upgrading to 4.1.24 and modifying the XSL file. Worked perfectly. 


FYI, there’s been some similar issues with other users in the “Pix4d user group” on facebook. 

@Derrick, I’m glad to hear that Rhéa’s recommendation got you back up and running with 4.1.24 and thank you very much for sharing the latest information on the Pix4D User’s Group on Facebook; we greatly appreciate it.