Norton Product Tamper Protection Unauthorized access blocked (Access Process Data)

The Unauthorized Access Blocked messages in your security history are logged by Norton Product Tamper Protection when an executable file attempts to read/write/edit/delete a Norton file.  Common Windows processes like svchost.exe, taskmgr.exe, dfrgntfs.exe, etc. as well as executable from third-party software will cause an Unauthorized Access Blocked message to be logged if they touch a file from your Norton installation. Please see post <here> in the Product Suggestions board regarding logging of these blocks. (credit Imacri)

Norton Product Tamper Protection events are not reports of malware.  Unauthorized Access Blocked (Access Process Data) messages in your security history are not reports of malware.  The most common Norton Product Tamper Protection log entries are legitimate Windows processes that Norton is preventing from accessing Norton files or processes.  

Norton Product Tamper Protection events are normal, as legitimate programs and Windows processes frequently try to access Norton files or processes.  Norton blocks attempts by outside agents - even legitimate Windows processes.  There is no need to do anything.  No need to scan with a third-party anti-malware program, no need to change services settings.  These events are not attacks.  They can be ignored.  Unless the actor in the logs is an actual malicious process that does not belong on your PC, these events are totally harmless and routine. (credit SendOfJive)