df -h $ORACLE_HOME df -h /tmp
OPatch always writes a detailed log. The location depends on your command, but typically it is: opatch failed with error code 21
To resolve this error, follow these standard Oracle maintenance procedures: df -h $ORACLE_HOME df -h /tmp OPatch always
opatch apply -debug
If the log indicates file locking, you must find the process holding the file. opatch failed with error code 21
: If you are on Windows, ensure all Oracle services (including the Distributed Transaction Coordinator) are stopped, as active files can block the patching process.