Prerequisite check "CheckActiveFilesAndExecutables" failed

APPLIES TO:

Oracle Database - Enterprise Edition - Version 9.2.0.1 to 11.2.0.3 [Release 9.2 to 11.2]
Information in this document applies to any platform.
Checked for relevance on 11-Jan-2012

SYMPTOMS

While trying to apply or rollback any patch using OPatch, it fails with the following error:

CAUSE

According to the above  error message, oracle binary ($ORACLE_HOME/bin/oracle) is still active or in use.
It can also  fail with other ORACLE_HOME active files/libraries .
Example:
/u01/app/oracle/10.2.0/bin/tnslsnr
/u01/app/oracle/11.2.0.3/lib/libclntsh.so.11.1

SOLUTION

Verify and ensure that all database instances/services that are running from the $ORACLE_HOME being patched are cleanly shutdown.
Also  identify the process that is using these active files/libraries.Then stop the process who is still accessing it and then apply/rollback the patch.