After installation of December 2016 Update for Dynamics 365 I cannot edit Workflows. I'm getting following error when I try to open Draft workflow:
Error Details:
Exception retrieving custom activity info - Object reference not set to an instance of an object.
Full Stack:
[CrmException: Exception retrieving custom activity info - Object reference not set to an instance of an object.] at Microsoft.Crm.Workflow.ObjectModel.CustomActivityInfoMetadataBase.GetCustomActivityInfo(ActivityInfo activityInfo, Int32 isolationMode) at Microsoft.Crm.Workflow.ObjectModel.CustomActivityInfoMetadataBase.GetCustomActivityInfo(Guid pluginTypeId) at Microsoft.Crm.Web.Sfa.WorkflowDetailPage.ConfigureCustomActivityStepMenu(CommandBarPopup addStepButton) at Microsoft.Crm.Web.Sfa.WorkflowDetailPage.BuildStepMenu() at Microsoft.Crm.Web.Sfa.WorkflowDetailPage.ConfigureWorkflowStepMenu() at Microsoft.Crm.Web.Sfa.WorkflowDetailPage.ConfigureMenus() at Microsoft.Crm.Application.Controls.AppUIPage.OnPreRender(EventArgs e) at Microsoft.Crm.Application.Controls.PageManager.OnPreRender(EventArgs e) at System.Web.UI.Control.PreRenderRecursiveInternal() at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) [HttpUnhandledException: Exception of type 'System.Web.HttpUnhandledException' was thrown.] 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.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)
Other Message:
Error Number:
0x8004501D