I noticed there hasn't been an update on this issue yet and the last patch for 6.12 was released on 8-9-2018. We have a customer that's migrating from a different DM system that has run into this when cleaning up index entries from the import. If it's any help here is the associated error from the Platform Error Log:
New entry --------------------------------------------------------------------------------
System.NullReferenceException: Object reference not set to an instance of an object.
Additional information:
TimeStamp : 2018-11-06T16:12:19.8581493Z
Machine : DOCUWARE
DocuwareUser : <RETRACTED>
StackTrace : at DocuWare.Platform.Implementation.Adapter.WafDialogsManager.TryGetDialogAdapter(String dialogId, IDialogAdapter& dialogAdapter, CabinetIdentity cabinetIdentity, DialogTypes[] dialogTypes)
at DocuWare.Platform.Implementation.Adapter.WafDialogsManager.GetDialogAdapter(String dialogId, CabinetIdentity cabinetIdentity, DialogTypes[] dialogTypes)
at DocuWare.Platform.Implementation.Adapter.CabinetAdapter.GetDialogAdapter(String dialogId, DialogTypes[] dialogTypes)
at DocuWare.Platform.Implementation.Models.DialogModel.GetSelectListResult(String dialogId, SelectListExpression selectListExpression)
at DocuWare.Platform.Implementation.Models.Decorators.MethodExecutor.Execute[TResult,T1,T2](Func`3 func, T1 arg1, T2 arg2, String methodName)
at DocuWare.Platform.Implementation.Models.Decorators.RetriableMethodExecutor.<>c__DisplayClass9_0`3.<Execute>b__0()
at Polly.Policy.<>c__DisplayClass8_0`1.<Execute>b__0()
at Polly.RetrySyntax.<>c__DisplayClass12_0.<WaitAndRetry>b__1()
at Polly.Retry.RetryEngine.Implementation[TResult](Func`1 action, IEnumerable`1 shouldRetryExceptionPredicates, IEnumerable`1 shouldRetryResultPredicates, Func`1 policyStateFactory)
at Polly.RetrySyntax.<>c__DisplayClass12_1.<WaitAndRetry>b__0(Action action, Context context)
at Polly.Policy.Execute[TResult](Func`1 action, Context context)
at Polly.Policy.Execute[TResult](Func`1 action)
at DocuWare.Platform.Implementation.Models.Decorators.RetriableMethodExecutor.Execute[TResult,T1,T2](Func`3 func, T1 arg1, T2 arg2, String methodName)
at DocuWare.Platform.Implementation.Models.Decorators.SafeMethodExecutor.Execute[TResult,T1,T2](Func`3 func, T1 arg1, T2 arg2, String methodName)
at DocuWare.Platform.Implementation.Models.Decorators.LoggingExecutor.Execute[TResult,T1,T2](Func`3 func, T1 arg1, T2 arg2, String methodName)
at DocuWare.Platform.Implementation.Models.Decorators.ExecutableDialogModel.GetSelectListResult(String dialogId, SelectListExpression selectListExpression)
at DocuWare.Platform.Controllers.QueryController.ExecuteSelectList(String fileCabinetId, String dialogId, SelectListExpression selectListQueryExpression, String q)
at DocuWare.Platform.Controllers.QueryController.SelectListExpression(String fileCabinetId, String dialogId, String fieldName)
at lambda_method(Closure , ControllerBase , Object[] )
at System.Web.Mvc.ActionMethodDispatcher.Execute(ControllerBase controller, Object[] parameters)
at System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters)
at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters)
at System.Web.Mvc.Async.AsyncControllerActionInvoker.<BeginInvokeSynchronousActionMethod>b__39(IAsyncResult asyncResult, ActionInvocation innerInvokeState)
at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult`2.CallEndDelegate(IAsyncResult asyncResult)
at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.End()
at System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult)
at System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3d()
at System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.<>c__DisplayClass46.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3f()
at System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.<>c__DisplayClass46.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3f()
at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass33.<BeginInvokeActionMethodWithFilters>b__32(IAsyncResult asyncResult)
at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult`1.CallEndDelegate(IAsyncResult asyncResult)
at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.End()
at System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethodWithFilters(IAsyncResult asyncResult)
at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass21.<>c__DisplayClass2b.<BeginInvokeAction>b__1c()
at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass21.<BeginInvokeAction>b__1e(IAsyncResult asyncResult)
Logging Level : Error
Message Text : System.NullReferenceException: Object reference not set to an instance of an object.
Assembly : DocuWare.PlatformImplementation, Version=6.12.0.0, Culture=neutral, PublicKeyToken=879da714589ba9ea
Code location - calling class : CombinedMemoryAndFileLog
Code location - calling method : Void LogWithDWLog(DocuWare.Web.Model.Logging.LogMessageTemplate)
Computer name : DOCUWARE
Date : 2018/11/06
Time : 10:12:22 AM
DocuWare.Common.Logging.TimeMS : 607
Application : w3wp
Thread ID : 9
Windows ID : <RETRACTED>