CefSharp - Could not load file or assembly 'CefSharp.Core.dll' or one of its dependencies

Question

I've been working on a CefSharp WinForms app for a few weeks and I've had no issues with it. This morning, while adding a few things to the application, I tried to run it to test something and got the below error:

System.IO.FileNotFoundException was unhandled Message: An unhandled exception of type 'System.IO.FileNotFoundException' occurred in mscorlib.dll Additional information: Could not load file or assembly 'CefSharp.Core.dll' or one of its dependencies. The specified module could not be found.

After searching for a while I found this:

https://github.com/cefsharp/CefSharp/wiki/Frequently-asked-questions#Runtime_dependencies

I checked bin/Debug/x86 for the project and all of the dependencies appear to be present. More importantly, it had been working fine five minutes earlier, and I didn't touch anything beyond a single class for an Entity Framework migration.

I've tried cleaning and rebuilding the solution, restarting Visual Studio, restarting my PC, and clearing out /bin/Debug, and none of these have helped.

Why would this error appear now after several days without it, and how can I resolve the issue?

Edit: I've done some further experimenting and I'm able to get the application to run in Release mode but not Debug mode. If I change the output path of Release mode to Debug, it fails with the same error (likewise, it succeeds in Debug with the Release output path).

Answer 1

First, make sure you installed the Microsoft Visual C++ Redistributable:

• Version v93 and above: use Microsoft Visual C++ 2019 Redistributable or greater
• Version v65 - v92: use Microsoft Visual C++ 2015 Redistributable or greater
• Older Versions: use Microsoft Visual C++ 2013 Redistributable (exact version)

You could download the Visual C++ Redistributable from Microsoft. See C++ binary compatibility between Visual Studio versions for more detail on the version compatability.

Make sure to match the correct architecture, if your application is x64, you need to install the x64 build of Visual C++ Redistributable. Likewise if your application is x86 then you need to install the x86 build of Visual C++ Redistributable.

The Microsoft Visual C++ Redistributable depends on the Universal CRT. The Universal CRT is included as part of Windows 10/11. On older versions of Windows the Visual C++ Redistributable will install the Universal CRT.

For those wishing to include the Visual C++ Runtime with their application it's technically possible to include the runtime with your application. See also Local Deployment section of the Deployment in Visual C++ article from Microsoft.