Windows Service: The module was expected to contain an assembly manifest

Question

I've got a C# program that was built as a Windows service. I tested this last week and it worked fine, but today I'm getting an error.

When I try to install using installutil.exe, I get the error:

Could not load file or assembly [file name] or one of its dependencies. The module was expected to contain an assembly manifest.

Rebuilding the project had no effect. I also noticed in task manager that the service is still listed and running. On the chance that might be interfering with the installation, I tried uninstalling via installutil, but got the same error message back again.

I've seen many other questions related to this error, but most of them have either no answer, or a very specific answer related to their unique situation. Has anybody had this happen, and how did you fix it? Any ideas are appreciated.

Update:

I successfully uninstalled the service using the "sc delete" command via command prompt, but I'm still getting the same error from installutil on trying to reinstall.

Update 2:

Just for the sake of trying something, I deleted the bin folder from the project, reopened the solution, and did a clean and build. It still won't install, but now I've got a different message:

This assembly is built by a runtime newer than the currently loaded runtime and cannot be loaded.

Question:

What would cause there to be a mismatch in runtimes? As far as I know, I've only used .NET Framework 4.5 and haven't deviated. Is there a value I should be looking at / changing to fix that?

Update 3:

Here's what I've tried so far:

One answer suggested the version of installutil being used matters. I'd been running v2.0.50727, but there's also a v4.0.30319 I hadn't thought to try. Running this resulted in:

An attempt was made to load a program with an incorrect format...

I'd be willing to work on that error instead, if it would solve the problem. However, I'm compelled to think that's not the problem since I'd been successfully running v2.0.etc just before the first error popped up.

Inside App.config, there's a line "supported Runtime version=v4.0". I switched this to 4.5, but it had no effect good or bad.

I tried switching the target framework (under project properties) down to 4.0, but this cause an error with:

Some NuGet packages were installed using a target framework different from the current target framework, etc...

This was referring to the EntityFramework, and I'd rather not start messing with NuGet again unless it's the only way (last time it was a nightmare).

I tried installing the service on the target server (the machine it will eventually be deployed to) and got the same error. This leads me to think it's a problem with the project / solution and not the pc.

Answer 1

Looks like a assembly loading problem. Use the Fuslogvw.exe utility. Start it from the Visual Studio Command Prompt. Click the Settings button and click the "Log binding failures to disk" radio button. Switch back to VS and start the program and wait for the exception to occur. Back to Fuslogvw, click the Refresh button and double-click the added entry. It will show you the file it found.

One another possibility is to trying to load a .NET 4 assembly with an EXE that asked for CLR version 2. That requires an app.exe.config file that forces CLR 4 to be used.