I am a domain admin and goes to Central Administration->Backup and Restore.
When selecting "Perform a backup" (which have been working before) I receive the following error (copied from log):
System.Reflection.AmbiguousMatchException: Multiple custom attributes of the same type found.at System.Attribute.GetCustomAttribute(MemberInfo element, Type attributeType, Boolean inherit)
at Microsoft.SharePoint.Administration.SPIisWebServiceApplication.get_BackupBehavior()
at Microsoft.SharePoint.Administration.Backup.SPBackupRestoreSharedServicesApplications.AddSPPersistedChildren(SPBackupRestoreObject self)
at Microsoft.SharePoint.Administration.Backup.SPBackupRestoreSharedServicesApplications.AddBackupObjects(SPBackupRestoreObject parent)
at Microsoft.SharePoint.Administration.Backup.SPBackupRestoreSharedServices.AddBackupObjects(SPBackupRestoreObject parent)
at Microsoft.SharePoint.Administration.SPFarm.AddBackupObjects(SPBackupRestoreObject parent)
at Microsoft.SharePoint.Administration.Backup.SPBackupRestore.CreateTree(IBackupRestore root)
at Microsoft.SharePoint.Administration.Backup.SPBackup..ctor(SPBackupRestoreSettings settings, SPBackupRestoreHistory mainHistory, SPBackupRestoreHistoryObject history)
at Microsoft.SharePoint.Administration.Backup.SPBackupRestoreConsole.CreateBackup(SPBackupRestoreSettings settings, SPBackupRestoreHistory history)
at Microsoft.SharePoint.Administration.Backup.SPBackupRestoreConsole.CreateBackupRestore(SPBackupRestoreSettings settings, Boolean showTree)
at Microsoft.SharePoint.Administration.Backup.SPBackupRestoreConsole.CreateBackupRestore(SPBackupRestoreSettings settings)
at ASP._admin_backup_aspx.__Render__control9(HtmlTextWriter __w, Control parameterContainer)
at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
at System.Web.UI.HtmlControls.HtmlForm.RenderChildren(HtmlTextWriter writer)
at System.Web.UI.HtmlControls.HtmlForm.Render(HtmlTextWriter output)
at System.Web.UI.HtmlControls.HtmlForm.RenderControl(HtmlTextWriter writer)
at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
at System.Web.UI.HtmlControls.HtmlContainerControl.Render(HtmlTextWriter writer)
at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
at System.Web.UI.Page.Render(HtmlTextWriter writer)
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)