Opatch fails with Lock file error

While applying Oracle Patch, Opatch reports the below error :

OUI-67064:OPatchSession cannot load inventory for the given Oracle Home /ora01/app/oracbr/product/11.2.0/dbhome_1. Possible causes are:
                               No read or write permission to ORACLE_HOME/.patch_storage
                               Central Inventory is locked by another OUI instance
                               No read permission to Central Inventory
                               The lock file exists in ORACLE_HOME/.patch_storage
                               The Oracle Home does not exist in Central Inventory
[Dec 20, 2013 8:29:05 AM]    OUI-67073:UtilSession failed: Lock file left by a different patch, OPatch will not try re-using the lock file.




Note : It has been noticed that opatch lock error also leads to the error "OPatch failed with error code 255"



In earlier releases, error used to look like:

Problems with the lock file
Lock file exists, details are:
Interim Patch is holding the lock from this patch xxxxxx,
probably due to previous unsuccessful operation

ERROR: OPatch failed during pre-reqs check



CAUSE
 When Opatch is invoked, it creates patch_locked file in $ORACLE_HOME/.patch_storage during its execution.

 If the patch application is interrupted or cancelled, this file gets retained under /.patch_storage directory. Hence, On an an attempt to re-apply the patch, the presence of patch_locked file doesnt allow further processing and throw error.


SOLUTION
1. Check if the file "patch_locked" is present in the directory $ORACLE_HOME/.patch_storage

2. If present, rename, move or remove the patch_locked file from $ORACLE_HOME/.patch_storage

3. Re-apply the patch