When you try to migrate Projects, system throws below error message(s);
Milestone status not permitted; task ABC is not marked as milestone
Hierarchy not valid; only one task without right neighbor permitted
Reproducing the Issue
1. Go to the Business Configuration work center.
2. Go to the Overview view.
3. Find the Migration of Projects activity.
4. Select Migrate Projects using the migration tool.
5. Select the file.
6. Execute Migration Step by Step.
The cause for the error "Milestone status not permitted; task * is not marked as milestone" is because the field Milestone Status as "Not reached" and there is no data maintained for the fields Phase Indicator and Milestone Indicator and the reason fot the error "Hierarchy not valid; only one task without right neighbor permitted" is because there is no data maintained for the field Right Neighbor Task ID.
If any records satisfying the above criterion is found and the customer is marking the Milestone Status as Not reached then you have to maintain the field Phase Indicator or Milestone Indicator for all the records. Or else the field Milestone Status can be marked as Not Relevant in which there in no need to maintain the fields for Phase Indicator or Milestone Indicator.
For the error Hierarchy not valid; only one task without right neighbor permitted The reason for this is that in the migration template for Projects, Task Details worksheet, Right Neighbor Task ID has not been maintained for any of the Project Task IDs. Only the last Project Task ID will not have a right neighbor associated to it.
KBA , right neighbor task id , hierarchy not valid , migration of projects , AP-RC-BCT , Business Config. Tools (SAP Business ByDesign , How To