Diagnosis
A change request is locked when you change its processing status and itis processed directly (for example, by adding new objects). A changerequest is also locked when new objects or hierarchy relationships areadded. This occurs in single processing, data transfer (upload of masterdata, language-dependent texts or hierarchies), or in collectiveprocessing.
As a consequence, if a change request is used for multiple entity types,these cannot be processed simultaneously because each locks the samechange request.

Procedure
You can use transaction SM12 to view the locks. The lock table is calledUSMD120C and the lock arguments are the client and the technical key ofthe change request.