The definition of object with type 'Report Definition' ( ID : xxx ) is not readable
CAUSEIf this occurs from multiple Developer machines, using the Administrator user, against the same metadata then it is likely that the report's definition has become inconsistent and unreadable by any Strategy applications/layers.
ACTIONIn order to track down the cause of the inconsistency, customers encountering this issue should make note of related object manipulations, Object Migrations, or error messages prior to experiencing the problem. Change Journaling, if it has been enabled, can help in preserving this information.
WORKAROUNDThese types of reports cannot be salvaged. If a metadata containing an earlier working copy of the report exists then it may be used to migrate that earlier copy and replace the non-working one. Otherwise, deleting and recreating the report is the only way forward.