to complete an anti-virus or anti-malware scan depends
on a variety of factors
To speed up a scan
- The program itself and how its scanning engine is designed to scan: using a signature database vs heuristic scanning or a combination of both...see How an Anti-virus Program Works.
- Options to scan for rootkits, 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).
, clean out temporary (junk) files
first, 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
. You can also speed up a scan by using file exclusions...What Files Should You Exclude?
In most cases when performing routine security checks, only a Quick Scan is needed
since it checks the areas of your computer most likely to contain malware...the most prevalent and common places where malware typically hides. A Full Scan
is much more comprehensive and can take a long time since it checks the entire hard drive (all folders/files) which can number in the thousands. The length of time for performing this type of scan varies because it is so comprehensive and therefore can take several hours. As such, a Full scan is generally recommended only for heavily infected systems...showing obvious indications (signs of infection
and malware symptoms
) that something is wrong.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. Some files and services are locked by the operating system or running programs during use for protection, so security scanners may encounter problems attempting to access them. Other legitimate files, especially those used by security programs, may be obfuscated, encrypted or password protected in order to conceal itself so they do not allow access as a protective measure. Further it is not unusual for an anti-virus or anti-malware scanner to have problems with or be suspicious of compressed, archived, .cab, .rar, .jar, .iso, and packed files because they have difficulty reading what is inside them. These kind of files often trigger alerts by security software using heuristic detection because they are resistant to scanning (difficult to read). This resistance may also result in some scanners to stall (hang) on these particular types of files.