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

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).

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.

I had the same problem until I installed the following redistributable:

SuperBerry's solution of installing VC++ redistribution package solved the problem for me. I'll just provide a little troubleshooting insights from my naïve perspective.
The error message is pretty clear, either the assemble CefSharp.Core.dll is missing or one of it's dependencies. So the question boils down to how do you figure out what is missing?
So first, do you have CefSharp.Core.dll? In the Solution Explorer look at the references for the project that is having this problem. You should find a reference to CefSharp.Core. If you can't find one, you're missing that assembly. If you have one, then the problem is that you're missing one of its required dependencies. When you click on the CefSharp.Core reference, in the detail, you'll get the full path to where it's located. In my case, it was in located at 'C:\Users\tom\source\repos\MyProject\src\packages\CefSharp.Common.41.0.0\CefSharp\x86\CefSharp.Core.dll'.
You then need to get a list of the CefSharp.Core dependencies to figure out which dependency your missing. Dumpbin.exe is a command line tool that you can use to get a list of dependencies. In order to use dumpbin, you need to make sure that it can be found on the path in your system environment variables. I found on the path of the VC Tools bin directory. In my case, I found one at: 'C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.25.28610\bin\Hostx64\x64'. Open a Command Prompt terminal and navigate to the folder containing CefSharp.Core.dll and key in the following:
>dumpbin /dependents CefSharp.Core.dll
the result I got was:
Dump of file CefSharp.Core.dll
File Type: DLL
Image has the following dependencies:
KERNEL32.dll
MSVCP110.dll
MSVCR110.dll
libcef.dll
USER32.dll
mscoree.dll
Not having worked with Microsoft Visual Studio for a number of years, I had to try and figure out where those dependencies are suppose to be located so that they can be resolved. I simply did an internet search such as "where is Kernel32.dll located" doing that for each dll until I found the missing dll. In my case, I could not find MSVCR110.dll, so I strongly suspected that was my problem. I then did an internet search for "MSVCR110.dll is missing" and found out that it was part of the vc++ redistribution. (SuperBerry, you were right on your first point). I also found that it could be downloaded from: 'https://www.microsoft.com/en-us/download/details.aspx?id=30679'. I downloaded both the x86 and x64 versions (although I only needed the x86 version for this project). They are executables that when run installs them. After installing them I found a copy of it in 'C:\Windows\SysWOW64' and in 'C:/Windows\System32'. And low and behold this problem was resolved.
What I learned from this process, was that it was difficult to know whether you have the right VC++ redistribution package installed or not. I thought I would have been installed when visual studio was installed with the VC++ features enabled. I'm using visual studio community version 2019. The project I am working with was a project I cloned from a GitHub source. I'm still confused about VC++ redistribution versioning. For example, could I have installed some later version and would it have worked (i.e. backward compatibility)?

I had the same issue. what worked for me is to add
<CefSharpBuildAction>Content</CefSharpBuildAction>
to the first PropertyGroup inside the csproj of the project you are dealing with.

I had the same issue even in release mode. Going through GitHub CefSharp FAQs, NOTE 2 solved my issue.
If compiling from source (not recommended, use the Nuget packages) and you notice that you can no longer build in debug mode, but release builds work just fine you may need to repair your version of Visual Studio. This happens in rare cases where you will get the same exact message as a missing unmanaged .dll file as shown above.
Had to repair Visual Studio and all started working as before.

For my future me, had this same issue and every time i get this error when i start my .net core 3.1 wpf application in visual studio -> Could not load file or assembly 'CefSharp.Core.Runtime.
That cost me hours!
My Solution: Don't initialize Cef in your WinForm or WPF Window class.
You need to initialize this in your startup main/app. In my example i need to add this:
public App()
{
CefSettings _browserSettings = new CefSettings();
...
Cef.Initialize(_browserSettings);
}

Visual studio 2013 unable to load dll, specified module not found

I'v Visual studio 2013 Professional with update-4.
I have a DLL library, written in Visual C++ and compiled in Visual studio 2012.
I wrote a wrapper (DLLImport attribute) to call native c++ dll function through my C# methods. I have also installed Visual C++ redistributable 2012 for visual studio 2013. I have also placed C++ DLL file in current working directory (debug directory)... I also used dependency walker, but could't get any idea from dependency walker, because dependency walker has same error and message from those .exe and .dll modules which are properly working and this native c++ dll. So I can't get help from dependency walker.
but even all doing above, I'm unable to load C++ dll file through my code ...
I receive this error
"unable to load dll, the specified module couldn't be found. (Exception from HRESULT: 0x8007007E)
Please help me. Thanks

Visual Studio 2008 Setup Project does not include VC_redist

I know this must have been answered before, but I cannot find a reference...
Problem: How do I configure a Visual Studio setup project to include and install the VC redist package?
Info:
I am creating a Visual Studio 2008 C# Win Forms project that uses native code through a managed C++ dll. In order to install this program on users computers, I made a Visual Studio Setup project. The only problem is, I cannot seem to get the x86_redist package to be included in the install, thus, the program fails to launch on users computers who do not have VS. (Yes, this is a Release build.) I have attempted adding a PreRequisite in the C# program, and I have attempted adding a Merge Module in the setup program.
Thanks for the help!
More detail:
The exact error message is this: Exception caught! System.IO.FileLoadException: Could not load file or assembly "MyInterface, Version=1.0.5354.28734, ..." or one of its dependencies. The application has failed to start because the application configuration is incorrect. Reinstalling the application may fix the problem. (Exception from HRESULT: 0x800736B1)
That HRESULT is a COM Exception, and essentially seems to wave its hands and say "Something bad happened". Any hints?

System.DllNotFoundException: Unable to load DLL. No errors in Dev machine but error in target machines

I built a C# application with WPF on Visual Studio 2012 that uses C++ DLL and targets .NET4.5. I have two projects running, one for the C# project and the other for C++ DLL project. I released both projects into a folder that has a .exe for C# and a .dll for C++ in the same folder.
I run them on my machine where they were developed and everything works fine. I run the .exe in other machines and it throws this exception:
System.DllNotFoundException: Unable to load DLL
It's not recognizing the DLL that is in the same folder.
I tried many things and nothing seems to work. I followed the solution in this post but nothing worked.
The Dev and Target machine are identical. In Dev, Visual Studio 2012 is installed, but that's the only difference.
Code:
C#:
[DllImport(#"Wireless.dll", EntryPoint = "?cert_exists#certificate#CertFuncs##SAHHPBD#Z", CallingConvention = CallingConvention.Cdecl)]
static extern int cert_exists(int store, [MarshalAs(UnmanagedType.LPTStr)]string cert_str);
C++:
static int __declspec(dllexport) cert_exists(int type, LPCSTR cert_str);
Update:
If I install Visual Studio 2012 on the target machine, everything works fine. If I remove it, the application crashes again. Any ideas on what VS is adding that can make the application work?

Just a guess: install Microsoft Visual C++ 2012 Redistributable Package on the user's machine. The native DLL you use may have other dependencies which have to be installed (try Dependency Walker). If the native DLL requires for example registry settings, config files etc. these should also be present. It should be distributed to user machines the same way you installed it on the dev machine.

This is due to your project build configuration being "Debug"(Right click on the solution '' -> properties -> 'configuration properties -> You should see all the projects configuration set to 'Debug'). It requires visual studio installed wherever you are running the exe(which is built in "Debug" mode).
Inorder to avoid this, change the configuration to "Release" and rebuild your project.

C# Dll Import failure: "The application has failed to start because its side-by-side configuration is incorrect"

I have a c# .net 4 app , using vs 2010.
Im trying to import a c++ dll (built on vs 2005).
[DllImport("Card.dll")]
I get the failure:
Unable to load DLL 'Card.dll': The application has failed to start because its side-by-side configuration is incorrect. Please see the application event log or use the command-line sxstrace.exe tool for more detail. (Exception from HRESULT: 0x800736B1)
using sxstrace.exe I get:
ERROR: Cannot resolve reference Microsoft.VC80.DebugMFC,processorArchitecture="x86"
I also found out that:
MFC80D.DLL and MSVCR80D.DLL are missing
Notice this is not DebugCRT, as this problem was caused by using a Debug compiled DLL instead of Release. I now use the Release compiled dll and the problem is DebugMFC.
I've tried anything I could find online. In order to save time I will introduce what I tried, so I won't get this advises again:
1- I have installed Microsoft Visual C++ 2010 Redistributable Package + SP1 + Security updates
2- I have installed Microsoft Visual C++ 2008 Redistributable Package
3 - I have installed Microsoft Visual C++ 2005 Redistributable Package
4 - I tried running this app as "Release" and not as "Debug"
5 - I tried to set entryPoint to the DllImport
Non helped. I still get the same error. I didn't see any other advise online instead of the one listed above.
Can anyone help me?

Because it says "Cannot resolve reference Microsoft.VC80.DebugCRT,processorArchitecture="x86", that means you are missing a dependency on the debug crt runtimes for VC 8.0. This means you need to build a release, NOT debug, version of card.dll. Microsoft doesn't ship a redistributable package for debug CRT runtimes. Those only comes with visual studio. Therefore build a release version of card.dll, and that should help your situation.

Do you have control over building Card.dll? If yes, have a look at how it is built. It must be built with proper version of VC++ (the one delivered with VS 2005) with manifest enabled. Then, installing the 2005 Redist. package must solve the problem. In case you cannot build Card.dll yourself, you will have to analyse the embedded manifest (if any) and contact the authors to remedy the problem cooperatively.

A static library by default links to the dynamic runtime.
If you re-build the dll in VS2005, change your Configuration Properties | C/C++ | Code Generation | Runtime Library setting to static runtime to avoid that problem.

You can use Dependency Walker to try to figure out what dependencies your dll pulls. If it says it wants *d.dll, then it looks like it is not a release version. Ask your colleague to check build configuration.
To use debug version you can try the following:
Go to the c:\Program Files\Microsoft Visual Studio 9.0\VC\redist\Debug_NonRedist\x86\ (this is for Visual Studio 2008, x86, adjust the path according to your system).
Copy the Microsoft.VC90.DebugCRT and Microsoft.VC90.DebugMFC directories to the directory with your executable.
Adjust the assembly version in the manifest files in the copied directories (the declaration looks like: <assemblyIdentity type="win32" name="Microsoft.VC90.DebugCRT" version="9.0.30729.6161" processorArchitecture="x86" publicKeyToken="1fc8b3b9a1e18e3b"></assemblyIdentity>, change the 9.0.30729.6161 according to what your dll needs.
Try to run the application.
The needed assembly version can be found in the output of sxstrace or in the in the *.intermediate.manifest file alongside the dll in its build directory. Sorry, I do not have Visual Studio 2005 and can not give the exact number.