Unable to delete copy of a file that may be associated with norton search function

An old backup of a Norton file is causing me grief. It was copied by a remote backup app on my Western Digital PR4100 NAS device to another Western Digital PR4100 NAS device used only for backup. I decided to “tidy up” this Backup NAS device but am unable to access/change this file. It is in a deep directory structure of “\BACKUPPR4100\Chris\WD-Products\A-I\Broadcom\Symantec\Norton\Norton Utilities\Premium” (one of rthe reasons I wanted to move it) and is a pdf file called: “search.norton.com_protect_SSDCAT=321&lang=en&installSource=direct&source=direct&product=ngc&year=2015&guid=0EB98E10-23A2-4896-9EA9-74E5099D3839&locale=en_GB&geo=GB&doi=2024-02-26&version=22.24.1.6&plang=sym%3AEN&layouttype=ESD&buildname=Retail&heartbe“

It seems I do not have any access rights to this file (yet I was able to make a copy??). It was suggested this is because it is a Norton protected file in use by the application (why would it access more than the “live” version only?).

  1. Does anyone know what is happening here?
  2. What is this file related to?
  3. How can I remove this copy?