We have received the below error while working on the 6-node cluster patching. The patch has been applied on software GRID and RDBMS on all the node but the datapatch execution is failed with ORA-27477. rac06:dbp01:/u01/app/oracle/product/12.1.0.2/database/OPatch$ ./datapatch -verbose SQL Patching tool version 12.1.0.2.0 on Wed Oct 25 12:55:45 2017 Copyright (c) 2016, Oracle. All rights reserved. Log file for this invocation: /u01/app/oracle/cfgtoollogs/sqlpatch/sqlpatch_12298_2017_10_25_12_55_45/sqlpatch_invocation.log Connecting to database…OK Bootstrapping registry and package to current versions…done Queryable inventory could not determine the current opatch status. Execute ‘select dbms_sqlpatch.verify_queryable_inventory from dual’ and/or check the invocation log /u01/app/oracle/cfgtoollogs/sqlpatch/sqlpatch_12298_2017_10_25_12_55_45/sqlpatch_invocation.log for the complete error. Prereq check failed, exiting without installing any patches. Soluti...