After you install VSE 8.x, McShield self-terminates because it reaches the user-configurable timeout values (Scan Timeout).

In the Windows Event Viewer, you might see the following:

5051 event ID  C:\Program Files\McAfee\SystemCore\mcshield.exe took longer than 90000 ms to complete a request
5019 event ID  Exception in McShield.Exe!
Exception details follow: VSCORE.15.3.0.532
Exception code: 0x000000000C0000005
Exception in update callback thread

The third-party process touched the files while McShield scanned them, then McShield terminated to prevent a file lock. The scan did not time out, but instead halted the process because the file could not be scanned.