Be careful when installing Oracle 12c on Windows. The first stumbling block, the Oracle Home User could produce a lot of trouble for you later. If you are used to running your Instance and Listener with an extra Account for Exports to Windows Shares, NAS devices or RMAN Backups to external storages for example with Avamar, a toughtless click at software installation could destroy all your work and efforts. It only remains to set up everything from scratch because the once selected user is not changeable.
Under 10g and 11g it was very easy to change Listener and Instance from „local system“ to an (Active Directory) Account with neccessary write permissions to corresponding external filesystems. This behaviour ends with Oracle 12c. Unfortunately the Oracle documentation is very clear about that: „Oracle Home User cannot be changed post installation.“
If you choose „Create new Windows User“ or „Use Windows Built-in Account“ and want to convert it to an existing AD Account it is not possible to logon to the database, the listener didn’t start properly or you may get the following or similar error messages at the database startup:
ORA-01078: failure in processing system parameters
LRM-00109: could not open parameter file ‘INITSID.ORA’
There is no chance to avoid this problem. Of course you can try to give the local Oracle User someway access to the storage but that’s not common in a domain. The only real solution is a new installation and now choose “Use existing Windows User” specifying your domain:
Just another hint at the end treats the variety of the account. Oracle’s idea is to implement the user only as a service account, so don’t mix it up with an administrative account for your software installation. It is also not possible to choose an administrator account or a member of the admin group as Oracle Home User during installation: [INS-32095] Specified User has administrative privileges.
But there seems to be still some issues with persmissions. The Oracle VSS Writer Service permanently produces an error in the Sever Event Log. The documentation of Oracle VSS Writer Service tells us why: “Thus, the Windows user must be able to log in as SYSDBA to the Oracle database instances managed by the writer service.” But the Oracle Home User didn’t have these permission and taking the Oracle Home User into the ora_dba group didn’t help because it’s still not an administrative account: Volume Shadow Copy Service error: Unexpected error calling routine RegOpenKeyExW(-2147483646,SYSTEM\CurrentControlSet\Services\VSS\Diag,…). hr = 0x80070005, Access is denied.
A solution by Oracle reads in the MOS Note 19313580 as follows: “Take the Oracle Home User into the local admin group.” This is exactly the opposite of the statements in the oracle documentation regarding the 12c Home User.
My solution is another. Just change the Log On for the OracleVssWriter Service to Local System.
Alternatively you can choose an administrative Account who is a member of the ora_dba group.
Now you are clean.
More information regarding the new Oracle Home User you will get here: