IIS7 Failed to grant minimum permission requests

Question

I get this error when I'm using FileHelpers.dll, but my IIS is set to Full trust level so it should not be that way

That's the full stack trace:

    [PolicyException: Required permissions cannot be acquired.]
       System.Security.SecurityManager.ResolvePolicy(Evidence evidence, PermissionSet reqdPset, PermissionSet optPset, PermissionSet denyPset, PermissionSet& denied, Boolean checkExecutionPermission) +10238142
       System.Security.SecurityManager.ResolvePolicy(Evidence evidence, PermissionSet reqdPset, PermissionSet optPset, PermissionSet denyPset, PermissionSet& denied, Int32& securitySpecialFlags, Boolean checkExecutionPermission) +97

    [FileLoadException: Could not load file or assembly 'FileHelpers, Version=2.0.0.0, Culture=neutral, PublicKeyToken=3e0c08d59cc3d657' or one of its dependencies. Failed to grant minimum permission requests. (Exception from HRESULT: 0x80131417)]
       System.Reflection.Assembly._nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, Assembly locationHint, StackCrawlMark& stackMark, Boolean throwOnFileNotFound, Boolean forIntrospection) +0
       System.Reflection.Assembly.InternalLoad(AssemblyName assemblyRef, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection) +416
       System.Reflection.Assembly.InternalLoad(String assemblyString, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection) +166
       System.Reflection.Assembly.Load(String assemblyString) +35
       System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective) +190

    [ConfigurationErrorsException: Could not load file or assembly 'FileHelpers, Version=2.0.0.0, Culture=neutral, PublicKeyToken=3e0c08d59cc3d657' or one of its dependencies. Failed to grant minimum permission requests. (Exception from HRESULT: 0x80131417)]
       System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective) +11207304
       System.Web.Configuration.CompilationSection.LoadAllAssembliesFromAppDomainBinDirectory() +388
       System.Web.Configuration.CompilationSection.LoadAssembly(AssemblyInfo ai) +232
       System.Web.Configuration.AssemblyInfo.get_AssemblyInternal() +48
       System.Web.Compilation.BuildManager.GetReferencedAssemblies(CompilationSection compConfig) +210
       System.Web.Compilation.BuildProvidersCompiler..ctor(VirtualPath configPath, Boolean supportLocalization, String outputAssemblyName) +76
       System.Web.Compilation.ApplicationBuildProvider.GetGlobalAsaxBuildResult(Boolean isPrecompiledApp) +283
       System.Web.Compilation.BuildManager.CompileGlobalAsax() +50
       System.Web.Compilation.BuildManager.EnsureTopLevelFilesCompiled() +676

    [HttpException (0x80004005): Could not load file or assembly 'FileHelpers, Version=2.0.0.0, Culture=neutral, PublicKeyToken=3e0c08d59cc3d657' or one of its dependencies. Failed to grant minimum permission requests. (Exception from HRESULT: 0x80131417)]
       System.Web.Compilation.BuildManager.ReportTopLevelCompilationException() +76
       System.Web.Compilation.BuildManager.EnsureTopLevelFilesCompiled() +1012
       System.Web.Hosting.HostingEnvironment.Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory, HostingEnvironmentParameters hostingParameters) +1025

[HttpException (0x80004005): Could not load file or assembly 'FileHelpers, Version=2.0.0.0, Culture=neutral, PublicKeyToken=3e0c08d59cc3d657' or one of its dependencies. Failed to grant minimum permission requests. (Exception from HRESULT: 0x80131417)]
   System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +11301302
   System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +88
   System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context) +4338644

Answer 1

I had a similar problem when I rebuilt my dev machine with a clean Windows 7 install. After hunting around I discovered a solution that worked for me.

In your IIS application pool advanced settings, under "Process Model", set Load User Profile to true.

There are some other things to check like your trust level, but none of them applied to me (it was all full trust already on my dev machine). Setting the application pool to load user profile fixed it.