to complete an anti-virus or anti-malware scan depends
on a variety of factors
Note: Using two or more program 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.
- 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 size and used capacity (number of 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/CPU resources by the scanner.
- Other running processes and programs in the background.
- Whether the scanning engine stalls, hangs or freezes.
- Interference from malware.
- Interference from other security programs attempting to scan at the same time.
- Interference from other programs attempting to update (download/install) components from the Internet.
- Interference from the user (whether or not you use the computer during the scan).
You may also want to read How an Antivirus Program Works
.To speed up a scan
, uninstall unnecessary programs, clean out temporary files
, temporarily disable any other real-time protection tools
, close all open programs, perform a Quick Scan
instead of a Full one and do not use the computer during the scan
. In some case you may need to try scanning in safe mode