hi,

I'm trying to import a document type from some older version (7.10) to 10.0. I'm getting an error An error occurred Object reference not set to an instance of an object.

Exception Details System.NullReferenceException, System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e: Object reference not set to an instance of an object.

Stacktrace: t Umbraco.Cms.Infrastructure.Packaging.PackageDataInstallation.CreateContentTypeFromXml[T](XElement documentType, IReadOnlyDictionary2 importedContentTypes, IContentTypeBaseService1 service) at Umbraco.Cms.Infrastructure.Packaging.PackageDataInstallation.ImportDocumentTypes[T](IReadOnlyCollection1 unsortedDocumentTypes, Boolean importStructure, Int32 userId, IContentTypeBaseService1 service, IEnumerable`1& entityContainersInstalled) at Umbraco.Cms.Infrastructure.Packaging.PackageDataInstallation.ImportDocumentType(XElement docTypeElement, Int32 userId) at Umbraco.Cms.Web.BackOffice.Controllers.ContentTypeController.Import(String file) at lambdamethod9785(Closure , Object , Object[] ) at Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.SyncActionResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, Object controller, Object[] arguments) at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeActionMethodAsync() at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted) at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeNextActionFilterAsync() --- End of stack trace from previous location --- at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Rethrow(ActionExecutedContextSealed context) at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted) at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeInnerFilterAsync() --- End of stack trace from previous location --- at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Awaited|260(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)

Please help