PolicyException: Required permissions cannot be acquired — what does this error mean

Question

Got this error when trying to load an aspx page:

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:
[PolicyException: Required permissions cannot be acquired.]
   System.Security.SecurityManager.ResolvePolicy(Evidence evidence, PermissionSet reqdPset, PermissionSet optPset, PermissionSet denyPset, PermissionSet& denied, Boolean checkExecutionPermission) +2770052
   System.Security.SecurityManager.ResolvePolicy(Evidence evidence, PermissionSet reqdPset, PermissionSet optPset, PermissionSet denyPset, PermissionSet& denied, Int32& securitySpecialFlags, Boolean checkExecutionPermission) +57
[FileLoadException: Could not load file or assembly 'SQLite.NET, Version=0.21.1869.3794, Culture=neutral, PublicKeyToken=c273bd375e695f9c' 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.nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, Assembly locationHint, StackCrawlMark& stackMark, Boolean throwOnFileNotFound, Boolean forIntrospection) +54
   System.Reflection.Assembly.InternalLoad(AssemblyName assemblyRef, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection) +211
   System.Reflection.Assembly.InternalLoad(String assemblyString, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection) +141
   System.Reflection.Assembly.Load(String assemblyString) +25
   System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective) +32
[ConfigurationErrorsException: Could not load file or assembly 'SQLite.NET, Version=0.21.1869.3794, Culture=neutral, PublicKeyToken=c273bd375e695f9c' or one of its dependencies. Failed to grant minimum permission requests. (Exception from HRESULT: 0x80131417)]
   System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective) +596
   System.Web.Configuration.CompilationSection.LoadAllAssembliesFromAppDomainBinDirectory() +211
   System.Web.Configuration.CompilationSection.LoadAssembly(AssemblyInfo ai) +46
   System.Web.Compilation.BuildManager.GetReferencedAssemblies(CompilationSection compConfig) +177
   System.Web.Compilation.BuildProvidersCompiler..ctor(VirtualPath configPath, Boolean supportLocalization, String outputAssemblyName) +185
   System.Web.Compilation.ApplicationBuildProvider.GetGlobalAsaxBuildResult(Boolean isPrecompiledApp) +230
   System.Web.Compilation.BuildManager.CompileGlobalAsax() +49
   System.Web.Compilation.BuildManager.EnsureTopLevelFilesCompiled() +462
[HttpException (0x80004005): Could not load file or assembly 'SQLite.NET, Version=0.21.1869.3794, Culture=neutral, PublicKeyToken=c273bd375e695f9c' or one of its dependencies. Failed to grant minimum permission requests. (Exception from HRESULT: 0x80131417)]
   System.Web.Compilation.BuildManager.ReportTopLevelCompilationException() +57
   System.Web.Compilation.BuildManager.EnsureTopLevelFilesCompiled() +612
   System.Web.Hosting.HostingEnvironment.Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory, HostingEnvironmentParameters hostingParameters) +644
[HttpException (0x80004005): Could not load file or assembly 'SQLite.NET, Version=0.21.1869.3794, Culture=neutral, PublicKeyToken=c273bd375e695f9c' or one of its dependencies. Failed to grant minimum permission requests. (Exception from HRESULT: 0x80131417)]
   System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +3465427
   System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +69
   System.Web.HttpRuntime.ProcessRequestInternal(HttpWorkerRequest wr) +279

Solution 1

Do you have the web app configured as Medium Trust and the SQLite.NET assembly requires Full Trust?

See if adding this to your web.config fixes it:

<system.web>
    <securityPolicy>
        <trust level="Full" />
    </securityPolicy>
...
</system.web>

Or if you already have the trust tag, change the level to Full.

Solution 2

If slolife answer doesn't work, you can also try this from msdn (ASP.NET Trust Levels and Policy Files):

<system.web>
    <securityPolicy>
        <trustLevel name="Full"    policyFile="internal"/>
    </securityPolicy>
</system.web>