Updated on: June 21, 2024
Viruses are a huge threat, so it’s essential that you regularly scan for them. All computers come with some kind of built-in virus scanner, but it’s a good idea to invest in a third-party antivirus like Norton if possible, as they tend to offer better detection and advanced features.
Most premium antiviruses will automatically scan for threats, but manual scans are still effective. I recommend you run a full scan every week, but you may be wondering when is the best time.
Though you can run scans most of the time, you can’t if your device is in sleep mode. This is something you should be aware of, but it isn’t a big deal. I’ll explain how scans work and give you some tips about when to run them.
When Should You Run a Virus Scan?
Maintaining a schedule of routine scans is important to ensure your computer is always protected. I recommend running one every week. As for when, it’s generally best to pick a time when you aren’t using your computer or at least not planning to do anything that requires a lot of resources (like editing a video or playing a game). That said, some antiviruses use more resources than others. Cloud-based antiviruses tend to be more lightweight, so scans aren’t as demanding.
Most importantly, your computer needs to stay on. If you shut your computer down or initiate a restart, the scan won’t work. Make sure your device isn’t set to shut down or go to sleep after a certain period of inactivity. If you use a laptop, keep it plugged in. You may need to change your settings to turn off auto-sleep or auto-power.
Finally, it’s best to schedule a scan when you aren’t using your computer. This makes it less likely you’ll accidentally do anything to interfere with the process or get frustrated if your device slows down.
Remember that scans can take up to 4 hours, so plan accordingly.
Virus Scans and Sleep Mode
Unfortunately, you cannot run a virus scan in sleep mode. Most virus protection programs require the computer to be active to check for a virus in your computer.
However, as most virus scans run unobtrusively in the background of your device, you could always schedule your scan to run during your workday or leisure time, without it affecting your performance.
How Does a Virus Scan Work?
There are many different types of viruses and malware, and they can function differently. Each piece of malicious code exhibits a pattern of behavior called a signature. Your antivirus software learns to recognize those signatures every time you install or allow an update. Virus scanners compare the definition files to the files on your computer to look for a match; if a virus is detected, the scanner will block the virus to prevent it from causing harm.
After the scan is complete, many antivirus programs automatically quarantine or remove the threats. Most software will also repair and restore the affected files and return them to their original location. If any files cannot be restored, the software will move them to a location where they cannot harm your system. Instructions are then given for dealing with or removing quarantined items.
A good antivirus, like Norton, for example, will also create log reports to keep you informed. You should review the scan reports as they are a good source of information about current viruses.
Types of Virus Scans
Generally, most antivirus solutions offer three different types of scans:
Full Scan
Provides an in-depth analysis of your entire system, including:
- All hard drives
- Memory (RAM) system backups
- Startup folder and registry items
- This can take several hours, depending on how much data is stored on your computer. A full scan should be run monthly.
Custom Scan
- You can select only the locations you want to scan and set the scan to avoid specific drives or folders.
- It focuses on drives where the operating system and downloaded files are stored.
- This scan can also check external storage and other removable media for viruses.
Quick Scan
- This scan only analyzes locations where viruses and malware are commonly found.
- Some programs only scan for files that were modified since the last scan.
- Most quick scans only take a few minutes.
- They can help you determine whether you need to run a full scan.
Do Virus Scans Affect Computer Performance?
Scanning doesn’t harm your computer or your files, but you may experience some performance issues while the scan is running. All active software places some burden on your computer’s resources, and if you have an older computer, the scan may put more of a strain on your processor. Usually, though, the impact will be negligible. If you are running an older computer, you might want to choose a cloud-based antivirus scanner like Bitdefender.
To lessen the impact on your computer’s performance, ensure your computer meets the minimum system requirements for your specific software. In general, antivirus programs need at least 4 GB of RAM and a 1.5 GHz processor. You should also keep 10 to 15 percent of storage space free.
If you have some performance issues and have checked the system requirements, you may want to try a different antivirus program. The worst thing to do is uninstall your antivirus program completely or disable the virus scanner.
Can a Virus Scan Cause Computer Problems?
Some people may install one antivirus software along with other security software, such as an antispyware program. However, this can prevent the virus scans from protecting your computer properly. Virus scans use some of the available memory on the computer, so running more than one antivirus software can limit the resources left to function properly.
You can get a false virus alert if multiple programs run simultaneous scans on your computer, as they might misinterpret each other’s actions as harmful.
To avoid this:
- Research available antivirus software and review compatibility issues with your other software.
- Limit the number of programs you install — many vendors now offer antivirus software with other security features.
- Watch out for any issues with your computer including slow processing, error messages when updating virus definitions, and viruses not being detected.
Virus Scan Tips
To be certain your computer is virus-free:
- Ensure your antivirus program is running by checking the system tray for the antivirus icon.
- Schedule a weekly scan and confirm it actually ran.
- Check the status to see if any infected files were found.
- Make sure that your virus definition files are updated regularly.
Summary
Scanning your device for malware is essential, but there are some restrictions on when you should scan your device. Most importantly, any scan will be interrupted if your device goes into sleep mode. This will compromise the whole scan and force you to start over. Make sure to check your settings to confirm that your device will not enter sleep mode after a certain amount of time. If you use a laptop, make sure it’s plugged in.
Beyond that, it’s best to schedule a scan for a time when you aren’t using your computer for anything that requires a lot of power. Scans can take up to 4 hours so plan accordingly.
Frequently Asked Questions
Can virus scans run in Sleep Mode?
No, and it’s a fundamental limitation. There are various types of scans most antiviruses can run, but none of them will work if your computer is asleep. This isn’t a big deal, however. Just schedule scans for a time when you won’t be intensively using your device, and you should be able to keep it protected just fine.
What is Sleep Mode?
Sleep mode is a power-saving state that allows a computer to quickly resume full-power operation (typically within a few seconds) when you want to start working again. When it’s on, your computer can’t run anything but the most basic of functions. Virus scans are not possible when it’s enabled.
What happens to a scheduled virus scan if my computer goes into sleep mode?
If a scheduled virus scan is set to run while the computer is in sleep mode, it will not start. The scan will either be skipped or postponed until the computer is active again, depending on the antivirus software settings.