That's possibly this nasty:
https://kc.mcafee.com/corporate/index?page=content&id=KB65940"Problem 1
When trying to install Patch 1 for VirusScan Enterprise 8.7i on McAfee Host Intrusion Prevention (HIP) 7.0 client running build 7.0.0.976 (Patch 4) or lower, the following error is reported:
Error 1920: Service McAfee McShield failed to start. Verify that you have sufficient privileges to start system services.
Problem 2
Installation of Patch 1 for VirusScan Enterprise 8.7i is triggering Host IPS Signature 1001 violations on mfehidin.exe
Patch 1 for VirusScan Enterprise 8.7i fails to install on computers which have McAfee HIP 7.0 Agent for Windows (Patch 4 or lower) installed (HIP client systems) with IPS protection enabled (PREVENT - HIGH). This issue occurs with HIP content version 2616 or before."
"Cause
This is due to a missing internal exception for the Mcafee VSE mfehidin.exe. Critical updates during the VSE installation are blocked by the HIP agent shielding signature 1001.
Solution
This issue will be resolved in the HIP June content update of 9 June, 2009.
Workaround
Create an IPS exception for mfehidin.exe from the Host IPS event."
If it isn't HIPS, 8.7i without Patch 1 has a habit of doing this; patch 1 is supposed to fix it.