Why does VirusTotal not detect a McAfee Internet Security Suite virus?

Question

On my local system, I have McAfee's Internet Security Suite installed. It detected some file on my system as a Trojan. I sent this same file to VirusTotal, but all the scanners didn't detect anything, even though they have both McAfee and McAfee-GW-Edition listed as scanners. Why would it detect it on my system and not on VirusTotal?

Answer 1

From the FAQ:

VirusTotal's antivirus engines are commandline versions, so depending on the product, they will not behave exactly the same as the desktop versions: for instance, desktop solutions may use techniques based on behavioural analysis and count with personal firewalls that may decrease entry points and mitigate propagation, etc.

In VirusTotal desktop-oriented solutions coexist with perimeter-oriented solutions; heuristics in this latter group may be more aggressive and paranoid, since the impact of false positives is less visible in the perimeter. It is simply not fair to compare both groups.

Some of the solutions included in VirusTotal are parametrized (in coherence with the developer company's desire) with a different heuristic/agressiveness level than the official end-user default configuration.

(Emphasis mine)