How do I resolve 'FileNotFoundException: Could not load file or assembly 'PDFNet.dll' or one of its dependencies' [64-bit and .NET 4 specific]?

Q: I have added the PDFNet.dll to the Bin folder of my .Net ASP
project. Included it as a resource and it runs great in dev. I
deployed the website to production and get the following error. The
DLL is in the Bin folder of the website. Is there something else I
need to do?

[FileNotFoundException: Could not load file or assembly 'PDFNet.dll'
or one of its dependencies. The specified module could not be found.]
A: What is the variant of PDFNet that you are using (i.e. the name of
the ZIP file you downloaded from pdftron website)?

In case of PDFNet for .NET 4.0 you need VC 2010 redistributable on
your system (MSVCP100.DLL and MSVCR100.DLL). This is a standard
component of Visual Studio. In case your target machine does not
include this redistributable you can download it from here:

Microsoft VC 2010 Redistributable Package (x86):


Microsoft VC 2010 Redistributable Package (x64):

You can either install the redistributable on the target machine or
you can copy the above mentioned DLL in the same folder as PDFNet.

In case you are using VS2008 and 64-bit version of PDFNet 1.1-3.5
(i.e. you would need Microsoft VC 2008 Redistributable
Package (x64):

In case you are using (i.e. 32-bit version of PDFNet for
1.1-3.5), there is no need to install any redistributable package.

Note also that if you are targeting x64, you need to remove the 32bit PDFNet assembly reference form the project, and add the 64bit one, and make sure that copylocal:true is set.


I have PDFNet x64 for .Net 4.0 and VC++ already installed. But I am still facing this error. Please let me know what could be the possible reason?

Gowtham C

Please post the full error message you see.


Please find the full message below.

Exception": {
“Name”: “FileNotFoundException”,
“Message”: “Could not load file or assembly ‘PDFNet, Version=, Culture=neutral, PublicKeyToken=36167be3f67ac39c’ or one of its dependencies. The system cannot find the file specified.”

Also please find the PDFNet dll stored in the G Drive

Gowtham C

" or one of its dependencies."

Most likely this is the VC++ runtime dependency.

For PDFNet versions 7.0 and older, this is the VC++ 2010 runtimes. Starting with PDFNet 7.1 it is now the VC++ 2013 runtimes.

Please download the installer from MS and install on the target system, or add to your installer/deployment system to automate.

Hi Ryan,

I am having VC++ redistributable 2012 and above. So unable to install 2010 VC++. The issue can be resolved by placing PDFNet dll in the bin folder. However we are facing issue in the service fabric environment.

Exception type: ConfigurationErrorsException

Exception message: Could not load file or assembly ‘PDFNet.DLL’ or one of its dependencies. The specified module could not be found.

This error means either PDFNet.dll was not found, or one of the VC++ 2013 redistributables was not found.

You can try ProcessMonitor from SysInternals to see what is not being found, or perhaps Windows Event Viewer has info.

Otherwise you need to review your “service fabric” documentation, to find out how to load dependencies.

Can this VC++ dlls can be added as part of application depdencies? If yes, what dlls to be added. (note: our Service fabric node is empty and we are installing only our application on that) ?

Gowtham C

Sorry it is unclear what you are asking here.

The “application” is yours.

Since the VC++ runtimes are Not .NET assemblies I don’t think you can depend on them the same way in Visual Studio, they just have to be made available. But since they are a Microsoft dependency you should be able to find lots of documentation about them.