Getting strange BadImageFormatException: Cannot load a reference assembly for execution

Question

I'm getting a crazy system load issue, which I have not idea what it is. The error and the output from the

Server Error in '/' Application. Cannot load a reference assembly for
execution. Description: An unhandled exception occurred during the
execution of the current web request. Please review the stack trace
for more information about the error and where it originated in the
code.

Exception Details: System.BadImageFormatException: Cannot load a
reference assembly for execution.

Source Error:

An unhandled exception was generated during the execution of the
current web request. Information regarding the origin and location of
the exception can be identified using the exception stack trace below.

Stack Trace:

[BadImageFormatException: Cannot load a reference assembly for
execution.]

[BadImageFormatException: Could not load file or assembly 'System.IO'
or one of its dependencies. Reference assemblies should not be loaded
for execution.  They can only be loaded in the Reflection-only loader
context. (Exception from HRESULT: 0x80131058)]   
System.Reflection.RuntimeAssembly._nLoad(AssemblyName fileName, String
codeBase, Evidence assemblySecurity, RuntimeAssembly locationHint,
StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean
throwOnFileNotFound, Boolean forIntrospection, Boolean
suppressSecurityChecks) +0   
System.Reflection.RuntimeAssembly.nLoad(AssemblyName fileName, String
codeBase, Evidence assemblySecurity, RuntimeAssembly locationHint,
StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean
throwOnFileNotFound, Boolean forIntrospection, Boolean
suppressSecurityChecks) +36   
System.Reflection.RuntimeAssembly.InternalLoadAssemblyName(AssemblyName
assemblyRef, Evidence assemblySecurity, RuntimeAssembly reqAssembly,
StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean
throwOnFileNotFound, Boolean forIntrospection, Boolean
suppressSecurityChecks) +152   
System.Reflection.RuntimeAssembly.InternalLoad(String assemblyString,
Evidence assemblySecurity, StackCrawlMark& stackMark, IntPtr
pPrivHostBinder, Boolean forIntrospection) +77   
System.Reflection.RuntimeAssembly.InternalLoad(String assemblyString,
Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean
forIntrospection) +21    System.Reflection.Assembly.Load(String
assemblyString) +28   
System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String
assemblyName, Boolean starDirective) +38

[ConfigurationErrorsException: Could not load file or assembly
'System.IO' or one of its dependencies. Reference assemblies should
not be loaded for execution.  They can only be loaded in the
Reflection-only loader context. (Exception from HRESULT: 0x80131058)] 
System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String
assemblyName, Boolean starDirective) +726   
System.Web.Configuration.CompilationSection.LoadAllAssembliesFromAppDomainBinDirectory()
+196    System.Web.Configuration.CompilationSection.LoadAssembly(AssemblyInfo
ai) +45   
System.Web.Compilation.BuildManager.GetReferencedAssemblies(CompilationSection
compConfig) +172   
System.Web.Compilation.BuildManager.GetPreStartInitMethodsFromReferencedAssemblies()
+91    System.Web.Compilation.BuildManager.CallPreStartInitMethods(String
preStartInitListPath, Boolean& isRefAssemblyLoaded) +111   
System.Web.Compilation.BuildManager.ExecutePreAppStart() +156   
System.Web.Hosting.HostingEnvironment.Initialize(ApplicationManager
appManager, IApplicationHost appHost, IConfigMapPathFactory
configMapPathFactory, HostingEnvironmentParameters hostingParameters,
PolicyLevel policyLevel, Exception appDomainCreationException) +695

[HttpException (0x80004005): Could not load file or assembly
'System.IO' or one of its dependencies. Reference assemblies should
not be loaded for execution.  They can only be loaded in the
Reflection-only loader context. (Exception from HRESULT: 0x80131058)] 
System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +659   
System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +89
System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest
wr, HttpContext context) +188


Version Information: Microsoft .NET Framework Version:4.0.30319;
ASP.NET Version:4.7.3160.0

When I look in fuslogvw, I get the following as the last error:

*** Assembly Binder Log Entry  (8/19/18 @ 12:10:13 PM) ***

The operation failed. Bind result: hr = 0x80070002. The system cannot
find the file specified.

Assembly manager loaded from: 
C:\Windows\Microsoft.NET\Framework64\v4.0.30319\clr.dll Running under
executable  C:\Program Files (x86)\Microsoft Visual
Studio\2017\Professional\MSBuild\15.0\Bin\Roslyn\VBCSCompiler.exe
--- A detailed error log follows. 

=== Pre-bind state information === LOG: DisplayName = System.Runtime.Loader, Version=4.0.0.0, Culture=neutral,
PublicKeyToken=b03f5f7f11d50a3a  (Fully-specified) LOG: Appbase =
file:///C:/Program Files (x86)/Microsoft Visual
Studio/2017/Professional/MSBuild/15.0/Bin/Roslyn/ LOG: Initial
PrivatePath = NULL LOG: Dynamic Base = NULL LOG: Cache Base = NULL
LOG: AppName = VBCSCompiler.exe Calling assembly :
Microsoft.CodeAnalysis, Version=2.9.0.0, Culture=neutral,
PublicKeyToken=31bf3856ad364e35.
=== LOG: This bind starts in default load context. LOG: Using application configuration file: C:\Program Files (x86)\Microsoft
Visual
Studio\2017\Professional\MSBuild\15.0\Bin\Roslyn\VBCSCompiler.exe.Config
LOG: Using host configuration file:  LOG: Using machine configuration
file from
C:\Windows\Microsoft.NET\Framework64\v4.0.30319\config\machine.config.
LOG: Post-policy reference: System.Runtime.Loader, Version=4.0.0.0,
Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a LOG: GAC Lookup was
unsuccessful. LOG: Attempting download of new URL file:///C:/Program
Files (x86)/Microsoft Visual
Studio/2017/Professional/MSBuild/15.0/Bin/Roslyn/System.Runtime.Loader.DLL.
LOG: Attempting download of new URL file:///C:/Program Files
(x86)/Microsoft Visual
Studio/2017/Professional/MSBuild/15.0/Bin/Roslyn/System.Runtime.Loader/System.Runtime.Loader.DLL.
LOG: Attempting download of new URL file:///C:/Program Files
(x86)/Microsoft Visual
Studio/2017/Professional/MSBuild/15.0/Bin/Roslyn/System.Runtime.Loader.EXE.
LOG: Attempting download of new URL file:///C:/Program Files
(x86)/Microsoft Visual
Studio/2017/Professional/MSBuild/15.0/Bin/Roslyn/System.Runtime.Loader/System.Runtime.Loader.EXE.
LOG: All probing URLs attempted and failed.

Answer 1

I have the same issue since I upgraded to .Net Framework 4.7.2. Deleting the bin folder makes the error go away.