Sitecore“随机”对象引用未设置为对象的实例

今天早上我突然去上班，做了一个最新版本，然后我开始使用Sitecore 6.5，我的工作状况还不错

[NullReferenceException: Object reference not set to an instance of an object.]
   Sitecore.Shell.Applications.ContentEditor.Editors.Folder.FolderPage.Render() +358
   System.Web.UI.Control.LoadRecursive() +70
   System.Web.UI.Control.LoadRecursive() +189
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +3177

另外，有时在打开文件夹时出现此错误：

>    [InvalidOperationException: The Sitecore.Client.Device is null.]
>     Sitecore.Client.get_Device() +86    Sitecore.UIUtil.GetBrowserClassString() +326   
> Sitecore.sitecore.login.LoginPage.AddBrowserAttributes() +135   
> Sitecore.sitecore.login.LoginPage.OnPreRender(EventArgs e) +435   
> System.Web.UI.Control.PreRenderRecursiveInternal() +113   
> System.Web.UI.Page.ProcessRequestMain(Boolean
> includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
>         +4297

任何想法如何解决它？