Oracle Error Message
ORA-19942: datafile copy string not created with compatibility 10.0 or greater
Reason for the Error
The specified datafile copy to be converted at the target was not produced after making the tablespace in read/write mode with compatibility 10.0 or greater at the source database.
Solution
Make a new datafile copy taken after tablespace has been made read/write with compatibility 10.0 at source database and retry conversion.