Cause
The specified Oracle base location is identical to an existing Oracle home location.
The specified Oracle base location is identical to an existing Oracle home location.
Specify a location for Oracle base which is not an existing Oracle home.
Try the following links for this error:
http://docs.oracle.com/cd/E16655_01/server.121/e26079/common_errormessages.htm
https://community.oracle.com/message/9415053
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