I told him he should run one right after the other but do not scan with both at the at the same time. Am I wrong ?
You are correct. In fact, its better to disable one of them before doing a scan. Using two security scanning engines at the same time can cause each to interfere with the other, cause systems hangs, false detections, unreliable results and other unpredictable behavior.
to complete an anti-virus or anti-malware scan depends
on a variety of factors
- The program itself and how its scanning engine is designed to scan: using a signature database vs heuristic scanning or a combination of both.
- Options to scan for spyware, adware, riskware and potentially unwanted programs (PUPS).
- Options to scan memory, boot sectors, registry and alternate data streams (ADS).
- Type of scan performed: Deep, Quick or Custom scanning.
- What action has to be performed when malware is detected.
- A computer's hard drive size.
- Disk used capacity (number of files to include temporary files) that have to be scanned.
- Types of files (.exe, .dll, .sys, .cab, archived, compressed, packed, email, etc) that are scanned.
- Whether external drives are included in the scan.
- Competition for and utilization of system resources by the scanner.
- Other running processes and programs in the background.
- Interference from malware.
- Interference from the user.
To speed up your scans, uninstall unnecessary programs, clean out the temporary files
or use ATF Cleaner
first, temporarily disable any other real-time protection tools
, close all open programs and do not use
the computer during the scan.