ORA-19928: CONVERT of data files with undo segments between different endian is not supported.
Cause: Conversion of data files with undo segments was not supported between endianess. The only time that data files with undo segments can be converted is between the same endianess as part of convert database. Convert database between different endian is not supported.
Action: Do not attempt to convert data files with undo segments between different endian.