Unable to synchronize the project with the SharePoint tasks list due to a circularly-linked task
If you see this error “Unable to synchronize the project with the SharePoint tasks list due to a circularly-linked task” it is most likely because you linked a task to itself.
Notice in the task list, the Predecessor is the same as the Title.
So, to rid yourself of the error, remove the self-referencing task from the predecessors list, save the item, and go back to Open Schedule to get back into MS Project.
Note: See the task item edit form below. The predecessors list allows the selection of itself. This can’t happen in the create form, but it can when you edit an existing one. It would have been nice if Microsoft would have thought of this and changed the form to lookup GUIDs and refrained from using it’s own GUID. Obviously a seperate form form the create form would be needed, but I don’t think that would have been too much for MS to do. Perhaps in the RTM version it will be enhanced.