Ora-39126 Worker Unexpected Fatal Error In Kupw-worker.prepare-data-imp 71 Jun 2026

Check for known bugs:

: Using a newer export version to import into an older database version without setting the parameter correctly. Resource Issues

When the error is linked to a specific object type, the quickest workaround can be to exclude it from the operation. This is particularly effective for objects like table statistics ( EXCLUDE=STATISTICS ) or problematic Advanced Queuing (AQ) tables. While you may lose some data in the process, you can often recreate or re-import it later, allowing the main job to succeed.

For most modern Oracle versions (12c+), the most effective fix is to rebuild the Data Pump utility packages to clear internal corruption. Check for known bugs: : Using a newer

: The internal packages or views used by Data Pump may be invalid or corrupted. Missing or Incorrect Tablespaces

To isolate and resolve the issue, execute the following steps in sequence: Step 1: Locate the Underlying Error

The user executing the Data Pump job may lack the necessary privileges. For example, the exporting user might not be able to read a dependent object referenced in a view's DDL, or a database link used in the job might be invalid. Object access is another common culprit; for instance, a job might fail when a target object has been dropped or a dependent object is in an invalid state. While you may lose some data in the

is a generic "Worker unexpected fatal error" that occurs during Oracle Data Pump operations. The specific sub-program KUPW$WORKER.PREPARE_DATA_IMP [71] typically points to an internal failure while the worker is preparing to import data rows into a table. Primary Causes & Solutions

-- Run these as a user with SYSDBA privileges EXEC DBMS_STATS.GATHER_DICTIONARY_STATS; EXEC DBMS_STATS.GATHER_FIXED_OBJECTS_STATS; Use code with caution. Copied to clipboard 2. Rebuild Data Pump Components

If the error persists after statistics are updated, the Data Pump utility itself may need to be reloaded to fix potential internal package corruption. Navigate to your $ORACLE_HOME/rdbms/admin directory. Run the following script as SYSDBA : @dpload.sql Use code with caution. Copied to clipboard Missing or Incorrect Tablespaces To isolate and resolve

: The error appears consistently on the same table or row.

Using specific transformations like REMAP_TABLE or REMAP_TABLESPACE combined with tables containing complex data structures (LOBs, partitioned tables, nested collections, or identity columns) can lead to data dictionary mismatches if the target schema already contains a conflicting table skeleton.

If moving data across different Oracle releases, explicitly state the database version compatibility. If your target database is 19c and the source was 21c, add the target version to your command line:

The Oracle Data Pump error is a critical, generic unhandled internal exception that occurs during the initialization phase of a Data Pump import ( impdp ) job. It indicates that the internal Data Pump worker process ( KUPW$WORKER ) crashed while executing the PREPARE_DATA_IMP module. The number [71] acts as a specific positional or state marker within the Oracle kernel code, pointing to data structure validation or target metadata generation.

When doing a full import, avoid importing system schemas. Use the EXCLUDE parameter to skip these schemas in your impdp command: