Hi,

I am getting the following error after updating to version 10.8.6 patch, it just happening on one of our sites.

We are getting this error on what ever page we try to save.

Received an error from the server An error occurred

Method not found: 'System.Collections.Generic.IEnumerable1<Umbraco.Cms.Core.Models.Editors.UmbracoEntityReference> Umbraco.Cms.Core.PropertyEditors.DataValueReferenceFactoryCollection.GetAllReferences(Umbraco.Cms.Core.Models.IPropertyCollection, Umbraco.Cms.Core.PropertyEditors.PropertyEditorCollection)'. Exception Details System.MissingMethodException, System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e: Method not found: 'System.Collections.Generic.IEnumerable1

at Umbraco.Cms.Infrastructure.Persistence.Repositories.Implement.ContentRepositoryBase`3.PersistRelations(TEntity entity)

at Umbraco.Cms.Infrastructure.Persistence.Repositories.Implement.DocumentRepository.PersistUpdatedItem(IContent entity)

at Umbraco.Cms.Core.Cache.DefaultRepositoryCachePolicy2.Update(TEntity entity, Action1 persistUpdated)

at Umbraco.Cms.Core.Services.ContentService.CommitDocumentChangesInternal(ICoreScope scope, IContent content, EventMessages eventMessages, IReadOnlyCollection1 allLangs, IDictionary2 notificationState, Int32 userId, Boolean branchOne, Boolean branchRoot)

at Umbraco.Cms.Core.Services.ContentService.SaveAndPublish(IContent content, String culture, Int32 userId)

at Umbraco.Cms.Web.BackOffice.Controllers.ContentController.PublishInternal(ContentItemSave contentItem, String defaultCulture, String cultureForInvariantErrors, Boolean& wasCancelled, String[]& successfulCultures)

at Umbraco.Cms.Web.BackOffice.Controllers.ContentController.PostSaveInternal[TVariant](ContentItemSave contentItem, Func3 saveMethod, Func2 mapToDisplay)

at Umbraco.Cms.Web.BackOffice.Controllers.ContentController.PostSave(ContentItemSave contentItem)

at lambda_method5805(Closure , Object )

at Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.AwaitableObjectResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, Object controller, Object[] arguments)

at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.

at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.

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.

Thanks Darren