The first thing that comes to mind is that maybe you are low on resources - memory or spare disk space?
However, that's a wild guess and the only way of really checking it would be to have Technical Support check it out, it's free of charge by phone or online chat and linked under Useful Links at the top of this page.
Meanwhile try running the Virtual Technician to see if it finds and fixes any issues: http://mvt.mcafee.com/
You'll have to run it anyway prior to connecting to Technical Support so may as well try it first.
Meanwhile make sure that Windows is totally up to date, including IE - which should be IE11, whether or not you use it as your default browser.
Meanwhile try running the Virtual Technician
He (she?) already did
Virtual Technition also indicates no errors.
Don't forget I'm seeing McAfee updates crash McSvHost, so this might be a similar problem. The first thing to do is to check the Windows Event Logs for System & Application to look for any supporting information. Running sfc /scannow from the command line might also be needed in case any Windows system files have been corrupted.
There's always the uninstall / MCPR / re-install option, as I was reminded :-)
Crashing Windows Explorer is a major DoS, so until it's fixed perhaps McAfee Automatic Updating should be turned off (which is what I did. I now update at the end of a working session).
Sorry, that's me speed reading again.....maybe it's malware-based? Try running some of the tools in the last link in my signature below, before contacting support.
Is it due to the McPvNs.dll file, or the DLL being unloaded? It'll say what the faulting module is in the problem report. I'm having a similar issue, and from what I heard they were going to fix the shell extension in question. The last update to File Lock was made back in September from what the "About" window says.