Symantec Endpoint Protection (SEP) clients do not update definitions.
The issue has already been resolved by clearing corrupted definitions per the following article:
Potential Symantec Endpoint Protection content definition corruption
However files in the folders have "Access Denied"
Access Denied when accessing/deleting a definition file.
LANDesk Remote Control Application has locked the access to Symantec liveupdate content definition files.
It can be any application that is able to lock a process by accessing it for that instance, for example - explorer.exe.
Identify the exact files that are being locked. After identifying the affected files, for example definition.dat.
Run Process Explorer as Administrator > Find > Find Handle or DLL.
Search for definition.dat, note all processes and PID that are accessing the file (LANDesk is just an example of a process that can lock a file)
Kill any PID/process accessing the affected files.
A possible permanent solution for this is to contact LANDesk Support and/or patch/upgrade to latest version of this software if it is a 3rd party software.
Symantec Endpoint Protection 11.x and 12.1