CRS-6706: Oracle Clusterware Release patch level ('2104789788') does not match Software patch level ('448950863'). Oracle Clusterware cannot be started.

CRS-6706: Oracle Clusterware Release patch level ('nnn') does not match Software patch level ('mmm') (Doc ID 1639285.1)

For 12.1 version :

Execute"<GI_HOME>/crs/install/rootcrs.sh -patch" as root user on the problematic node and the patch level should be corrected.

For 12.2

Execute"<GI_HOME>/crs/install/rootcrs.pl -prepatch"  "<GI_HOME>/crs/install/rootcrs.pl -postpatch"and as root user on the problematic node and the patch level should be corrected.

If still not working, you can try below solution:

Patching 12.2.0.1 Grid Infrastructure gives error CRS-6706: Oracle Clusterware Release Patch Level ('748994161') Does Not Match Software Patch Level (Doc ID 2348013.1)

CAUSE

This issue was caused by rootcrs.sh -prepatch not run successfully before patching.  The user ran rootcrs.sh -unlock because rootcrs.sh -prepatch failed, and then applied the patch manually. 
 

SOLUTION

 Please use the following steps to complete the patching:

1.  Run the following command as the root user to complete the patching set up behind the scenes:
#GI_HOME/bin:>  ./clscfg -localpatch

2.  Run the following command as the root user to lock the GI home:
#GI_HOME/crs/install:>  ./rootcrs.sh -lock

3.  Run the following command as the root user to start the GI:
#GI_HOME/bin:>  ./crsctl start crs