Getting the following error while uploading (not installing), any Sitecore package:

9484 14:41:39 ERROR Could not resolve type name: **Sitecore.Pipelines.Upload.CheckExtension, Sitecore.UploadFilter** (method: Sitecore.Configuration.DefaultFactory.CreateFromTypeName(XmlNode configNode, String[] parameters, Boolean assert)).
9484 14:41:39 ERROR Application error.

Exception: System.Web.HttpUnhandledException
Message: Exception of type 'System.Web.HttpUnhandledException' was thrown.
Source: System.Web
at System.Web.UI.Page.HandleError(Exception e)
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
at System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
at System.Web.UI.Page.ProcessRequest()
at System.Web.UI.Page.ProcessRequest(HttpContext context)
at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
at System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step)
at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

2 Answers 2


It looks like configuration of your website includes reference to Upload Filter tool.

It is mentioned in Secure the file upload functionality Sitecore documentation:


Now it looks like the dll is missing. You have 2 options:

  • Copy right version of Upload Filter tool dll into bin folder
  • Remove config that mentions CheckExtension class (most probably App_Config\Include\UploadFilter.config)

As Marek mentioned, copy the Sitecore.UploadFilter.dll from Sitecore vanilla to the C:\inetpub\wwwroot\<website>\bin folder.

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