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Server Error in '/' Application.

Access to the path '636081729995142753' is denied.

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.UnauthorizedAccessException: Access to the path '636081729995142753' is denied. 
ASP.NET is not authorized to access the requested resource. Consider granting access rights to the resource to the ASP.NET request identity. ASP.NET has a base process identity (typically {MACHINE}\ASPNET on IIS 5 or Network Service on IIS 6 and IIS 7, and the configured application pool identity on IIS 7.5) that is used if the application is not impersonating. If the application is impersonating via <identity impersonate="true"/>, the identity will be the anonymous user (typically IUSR_MACHINENAME) or the authenticated request user. 
To grant ASP.NET access to a file, right-click the file in Explorer, choose "Properties" and select the Security tab. Click "Add" to add the appropriate user or group. Highlight the ASP.NET account, and check the boxes for the desired access.
Source Error:

Stack Trace:

[UnauthorizedAccessException: Access to the path '636081729995142753' is denied.]
   System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath) +12892983
   System.IO.FileInfo.Delete() +183
   ASP.global_asax.Application_Start(Object sender, EventArgs e) +283

[HttpException (0x80004005): Access to the path '636081729995142753' is denied.]
   System.Web.HttpApplicationFactory.EnsureAppStartCalledForIntegratedMode(HttpContext context, HttpApplication app) +3985477
   System.Web.HttpApplication.RegisterEventSubscriptionsWithIIS(IntPtr appContext, HttpContext context, MethodInfo[] handlers) +191
   System.Web.HttpApplication.InitSpecial(HttpApplicationState state, MethodInfo[] handlers, IntPtr appContext, HttpContext context) +325
   System.Web.HttpApplicationFactory.GetSpecialApplicationInstance(IntPtr appContext, HttpContext context) +407
   System.Web.Hosting.PipelineRuntime.InitializeApplication(IntPtr appContext) +375

[HttpException (0x80004005): Access to the path '636081729995142753' is denied.]
   System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +11524352
   System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +141
   System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context) +4782309

Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.1

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原因：出现这个问题是因为web.config没有修改权限导致的 解决方法：给网站目录写入权限，目录权限配置请见下面的相关文档。