TNS-12518: TNS:listener could not hand off client connection on 12c Upgrade
During a migration from 11.2.0.3 (SE) Windows 2008 R2 to 12.1.0.1 with patch 20558101 (12.1.0.1.18) I was getting the "ORA-12518: TNS:listener could not hand off client connection" error on a 11gR2 database using a 12c listener.
Errors in listener log:
03-JUN-2015 15:56:08 * (CONNECT_DATA=(SERVICE_NAME=MYTEST)(CID=(PROGRAM=d:\app\orcsvc\product\12.1.0\dbhome_1\bin\sqlplus.exe)(HOST=XXXXXXX)(USER=YYYYY))) * (ADDRESS=(PROTOCOL=tcp)(HOST=::1)(PORT=49443)) * establish * MYTEST* 12518
TNS-12518: TNS:listener could not hand off client connection
TNS-12560: TNS:protocol adapter error
TNS-00534: Failed to grant connection ownership to child
64-bit Windows Error: 10022: Unknown error
It turned out the 12c listener service was owned by the new Oracle Home User "orcsvc" but the 11gR2 database service was "Local System". Once I changed the service owner on the 12c listener to "Local Admin" everything was fine!