The 3 Types of Antivirus Scans and When to Use Each One

Gavin Phillips 02-05-2018

Regularly scanning your system with an antivirus program is one of the easiest ways to keep your system secure. Along with an antimalware suite, your antivirus is a core feature of your system security 10 Easy Ways to Never Get a Virus With a little basic training, you can completely avoid the problem of viruses and malware on your computers and mobile devices. Now you can calm down and enjoy the internet! Read More .


But what type of antivirus scan should you run? Are there differences between a Full scan, a Quick scan, and a Custom scan? Let’s take a look at what happens when you hit that “Scan” button.

How Does Antivirus Work?

Before considering exactly what each antivirus scan type does 3 Things Your Antivirus Doesn't Take Care Of Antivirus softwre should be installed on every computer, but what doesn't it take care of? Which aspects of your antivirus could leave you or your business exposed, even when you've installed and updated? Read More , let’s brush up on antivirus general role.

Your antivirus primarily works in the background of your system. It diligently notes your system files. When a file is modified, your antivirus scans it to ensure those changes aren’t harmful to your system.

The antivirus checks the properties of the file to make sure it isn’t part of a malicious program. Similarly, your antivirus suite has a long list of known malicious file signatures. If you download a file with a known signature, your antivirus should take care of it—but mishaps do happen occasionally.

Another antivirus trick is using behavioral analysis to assess unknown viruses. In this case, the antivirus doesn’t have a signature in its database to compare a file against. Instead, the antivirus monitors the actions of the file, inspecting the interactions on your system. If the file attempts certain activities on your system, the antivirus will quarantine the file.


Antivirus suites combine these two defense tactics and many others to keep your system free of malicious programs.

The Different Types of Antivirus Scans

Most antivirus programs have two or three different scanning options. In general, these options are usually a “Full” system scan, a “Custom” system scan, and a “Rapid/Hyper/Quick” scan option. This option is sometimes referred to as a “Smart” scan. The scan names are seemingly self-explanatory.

Full Scan

A full scan performs a thorough check of your entire system, inside and out. Depending on the antivirus program, the antivirus will scan the following objects:

  • All hard drives, removable storage, and network drives
  • System memory (RAM)
  • System backups
  • Startup folders
  • Registry items

A full system scan takes several hours, depending on how much data you have stored. In that, a full system scan is a thorough, in-depth analysis of everything on your system.


When to use? Use a full scan when you need to check your entire system. Some security experts advise completing a full scan every two weeks. But for most people, a single full scan per month is usually enough.

Custom Scan

The custom scan, then, allows you the same in-depth scanning functionality as a full scan, but you choose the locations to scan. For instance, my system has an SSD and three HDDs. Using Microsoft’s Windows Defender 4 Reasons to Use Windows Defender in Windows 10 In the past, Windows Defender was overshadowed by other options, but now it's quite a contender. Here are a few reasons why you should consider dropping your security suite in favor of Windows Defender. Read More , a full system scan takes hours to complete.

However, if you switch to a custom scan, you can tell the antivirus to avoid specific drives. If your system uses C: for your operating system and download folders, focus the scan there. At other times, if you encounter suspicious behavior, set your antivirus to scan the specific folder The Complete Malware Removal Guide Malware is everywhere these days, and eradicating malware from your system is a lengthy process, requiring guidance. If you think your computer is infected, this is the guide you need. Read More .

Some antivirus suites add a “Scan from this location” function to the right-click context menu within Windows. Similar functionality exists for macOS The Ultimate Mac Security Guide: 20 Ways to Protect Yourself Don't be a victim! Secure your Mac today with our exhaustive High Sierra security guide. Read More and numerous Linux distributions. (Check out these free Linux antivirus programs The 6 Best Free Linux Antivirus Programs Think Linux doesn't need antivirus? Think again. These free antivirus tools can ensure your Linux box remains virus-free. Read More .)


When to use? Use a custom scan to quickly analyze individual drives. A custom scan is a reliable way of checking external storage and other removable media for issues, too.

Hyper/Smart/Quick Scan

Finally, some antivirus tools have the option for a quick scan. This type of rapid system scan comes under different names, depending on the antivirus suite. So, how does a quick scan vary from a full scan?

  • Commonly infected files and folders
  • Running processes and threads
  • System memory (RAM)
  • Startup folders
  • Registry items

The quick scan item list looks very similar to the full scan list, right? That’s because it is. However, it has two major differences (again, these differences do vary slightly by antivirus suite).

First, a quick scan only analyzes locations where malware is likely to lurk, rather than every single file on your system. This alone drastically reduces the scan time. Second, some antivirus programs only scan for files that have been modified since the last scan. In this, the antivirus is skimming through data until it finds something worth notification.


In most cases, a quick scan should at least discover a virus, even if it doesn’t directly identify the variant or even the root directory of the infection. If your quick scan detects something serious, you can always switch to a full scan to try and uncover more infected files and information about what you’re dealing with.

When to use? The quick scan is a handy day-to-day tool. While a full scan is very resource heavy and time-consuming, a quick scan shouldn’t take more than a few minutes to complete. It gives you a great overall picture of your system health as well as whether you need to take further action against any lurking nasties.

Do Antimalware Suites Use Different Scans?

In a word, no.

Antimalware suites by and large use the same scanning criteria (startup folders, processes, registry items, and so on) as your antivirus. The difference comes in what the antimalware program is scanning for. Malwarebytes uses a different set of malicious signatures and behavioral analysis triggers than Windows Defender, for instance.

In that, using an antimalware tool alongside your antivirus is worthwhile. Malwarebytes Premium is an excellent antimalware solution for real-time protection 5 Reasons to Upgrade to Malwarebytes Premium: Yes, It's Worth It While the free version of Malwarebytes is awesome, the premium version has a bunch of useful and worthwhile features. Read More (the free version is a scan-only tool). However, there are some excellent free combined antivirus and antimalware tools The 10 Best Free Antivirus Software No matter what computer you're using, you need antivirus protection. Here are the best free antivirus tools you can use. Read More . If you want a well-rounded free tool, check out the latest version of Avast. Avast bought competitor AVG last year, and the merger has drastically improved the malware detection rate for Avast’s free offering.

Scan Your Computers for Safety

You now know the differences between antivirus scan types, as well as when you should use each one. Despite what some people say, you need to install and update your antivirus tool.

Unsure what you need? Check out our fantastic list of the best computer security and antivirus tools The Best Computer Security and Antivirus Tools Concerned about malware, ransomware, and viruses? Here are the best security and antivirus apps you need to stay protected. Read More .

Related topics: Antivirus, Computer Security.

Affiliate Disclosure: By buying the products we recommend, you help keep the site alive. Read more.

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  1. likefunbutnot
    May 8, 2018 at 2:08 pm

    There's really no such thing as "real time protection" from Malware. There are known threats, which can be blocked ahead of time based on some kind of digital thumbprint (this is something Spybot Search and Destroy offers), and there are threats that can be found and removed after the fact, because their behavior has been determined since the last scan to be malware.

    Malware does not meet the minimal criteria for virus-like behavior. It doesn't alter files in an attempt to replicate. It CAN do just about anything else, just like any other software on a computer. But because it doesn't have the recognizable trait of trying to create new infections, there's really no way to determine if something is bad or not without a direct, human decision that is presumably made by the antimalware vendor's engineers.

    In the case of something like Malwarebytes, it's not so much that you're being given real time protection as you are allowing a more or less continuous scan for malware to run.

    The author of this article also skips the incredibly useful tools related to advertising and script blocking in one's internet software. Those tools can do a huge amount of heavy lifting to keep malware from being delivered to a computer in the first place, and can also protect against pure javascript attacks (e.g. XSS) that wouldn't trigger antimalware blocking either. Tools like Adblock Plus, uBlock Origin, Noscript and uMatrix deserve to be discussed in this context. They do as much or more to keep computing devices safe than antivirus or antimalware at this point.

  2. Sajibul Islam Salim
    May 3, 2018 at 5:56 am

    I use two factor code genarator.And i lost my phone.I submit my id they give me rocovery code also.But that recovery code is expired.After then i submit my id again and again but they dont give me any code.Now what can i do for recover my account.

    If you have any suggestion please inform me at this