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Does a Factory Reset Remove All Viruses from Phones?

Hi there! Getting a virus on your smartphone can be super frustrating. You may have heard that performing a factory reset can wipe out weird bugs, glitches, and other issues caused by malware. But does resetting your device always fully remove viruses lurking on your system? Read on for the scoop.

The short answer is yes—most of the time a factory reset will erase viruses from your iPhone or Android device. Resetting your phone essentially gives you a blank slate again by erasing all downloaded apps, data, and customized settings. This wiping process deletes any infections that have made their way onto your system.

However, there are some clever smartphones viruses that know how to avoid deletion by hiding in tricky spots that survive a reset. While rare, these super stealthy viruses can occasionally slip past a factory restore.

So a reset offers a pretty thorough cleansing in most cases, but isn‘t an absolute guarantee to wipe every last bit of malware. Keep reading to learn when a reset will probably get the job done vs. when you may need to take extra steps.

Before we dive into the details, let‘s look quickly at what exactly a factory reset does to your phone:

A factory reset completely erases and restores your device back to its original out-of-the-box state. It‘s essentially like taking your phone back to day 1 when you first removed it from the box.

The reset process removes:

  • All downloaded apps
  • Music, photos, videos, and other media
  • Contacts, call logs, messages
  • WiFi passwords and other settings
  • Browser history and cache
  • Basically everything you‘ve added or customized on the device!

By wiping your phone of all apps and data, a factory reset also deletes any harmful malware that has made its way onto your system. Viruses have nowhere to hide when everything gets erased.

Resetting flushes out infections because it…

  • Erases infected system files full of malware code
  • Deletes apps containing viruses
  • Wipes the browser cache and history where pathogens hide
  • Returns settings modified by malware back to normal

Basically, it gives your phone a clean bill of health again by eradicating anything that doesn‘t belong in the factory-installed state.

Now that you know what a reset does, you can understand why it wipes out most viruses. By erasing everything after the initial install, any malware that found its way onto your device gets the boot.

According to research from antivirus companies like Norton and McAfee, factory resetting your phone removes somewhere around 95-99% of viruses, malware, spyware, ransomware, and other mobile threats.

For example, let‘s say you download a fun new game from the web that unfortunately contains nasty malware. A factory reset will wipe the infected game files from your phone and let you start fresh.

Or maybe you clicked a phishing link in a text message that secretly implanted spyware into your messaging apps. The reset eliminates the corrupted apps containing the spyware code.

In the vast majority of cases, a factory reset boots out infections picked up from:

  • Malicious apps & files
  • Phishing scams
  • Insecure WiFi networks
  • Suspicious links
  • Third-party app stores
  • Other unsafe sources

Unless the virus is extremely advanced, a reset essentially quarantines it by removing the apps and files it has infected.

Statistics show factory resetting your mobile device removes viruses around 95-99% of the time.

Although rare, there are some tricky situations where a factory reset won‘t fully eliminate an infection. This is often due to advanced "rootkit" malware that burrows deep into places a reset can‘t reach.

Here are a few examples of viruses that may persist after a factory reset:

  • System-level malware that injects code into the core operating system files. Since a reset often doesn‘t wipe absolutely everything, this type of virus can evade deletion.

  • Recovery partition malware that hides in the recovery/reset files themselves. The reset can‘t remove viruses embedded in the code it uses to reset everything else!

  • Bootloader or kernel-level malware that loads first thing when you power on your device. By infecting these early startup processes, the virus survives the reset sequence.

  • Firmware viruses that write into the firmware, which is super difficult to remove or update on phones. Firmware bugs have made headlines affecting iPhones, Android devices, and more.

  • SIM card malware that hides on the SIM card to reinject after the reset. Some viruses can clone themselves onto SIM cards.

  • Baseband processor malware targeting the baseband CPU controlling cellular, WiFi, and data connectivity. Since baseband software is independent from the main system, a reset may not touch it.

  • External storage malware on SD cards and external drives that can reinfect your phone post-reset.

While most malware doesn‘t have this level of sophistication, these types of persistent viruses do pop up from time to time. Advanced cybercriminal groups like NSO Group and HackingTeam have developed some of these stealthy mobile viruses.

The key is that these tricky viruses are still quite rare, and factory resetting serves as an effective cure against most standard malware you‘ll encounter. But it pays to be aware that a reset isn‘t guaranteed to solve every last case.

How can you tell if one of these sneaky viruses has managed to persist through a factory reset? Here are some clues:

  • Unusual activity starts right after a reset
  • Antivirus apps detect the threat again after resetting
  • Full system scans come up clean, but issues keep occurring
  • You reset multiple times and problems remain each time

If you keep seeing the same suspicious popups, slow performance, or other glitchy behavior immediately after resetting, that’s a red flag.

Make sure to run full scans with antivirus software from reliable cybersecurity companies like BitDefender, Norton, and McAfee after resetting. This can detect if any malware persists.

Pay attention to see if problems crop up before you have a chance to reinstall apps, download files, or access new networks. That likely indicates an infection lingering from before the reset.

Okay, now that you know how resets work and how effective they are against viruses, when should you pull the trigger on a factory reset?

Resetting your phone when you suspect malware gives you the assurance of wiping out most viruses for good. Here are common cases when a reset is your best bet:

  • You notice odd device behavior – Unexplained crashes, freezing, overheating, or battery drain can indicate malware. A reset clears it out.

  • Antivirus apps detect a virus – If your antivirus app finds an infection too tricky to remove normally, reset to wipe it out.

  • You suspect a malware download – If you recently downloaded a bad app or file, reset before the virus causes harm.

  • Your accounts show compromise – Hackers accessing your accounts via malware on your phone. Reset to boot them out.

  • Your phone won’t boot properly – A virus interfering with the boot process may require a reset to function again.

  • You want to wipe your phone before selling – Avoid spreading malware to the next owner by resetting to factory fresh.

  • You notice suspicious network activity – Unexpected data usage, installed apps contacting remote servers, and other questionable network traffic could indicate viruses a reset can stop.

Of course a factory reset takes time and wipes out your data. So don’t reset at the first sign of odd behavior—common troubleshooting steps may fix many issues before going nuclear. But resetting offers powerful virus protection when you really suspect malware.

Over 35 million Americans were victim to mobile malware and viruses in 2021 according to Lookout. Factory resetting phones infected with malware can help.

Since resetting erases everything on your phone, it should be a last resort after trying other options.

Here are some less drastic steps to attempt before factory resetting your device to remove a virus:

  • Run antivirus scans – Use a reputable mobile antivirus app to locate and isolate any infections. Malwarebytes, AVG, and others can detect and halt viruses.

  • Check for app updates – Make sure to install any available operating system and app updates. These often contain critical security patches.

  • Uninstall suspicious apps – Remove any apps you think may have been involved in the infection, like recently downloaded games or productivity tools.

  • Clear cache & browser data – Wipe out your browser history, cookies, temporary files, and caches where malware can lurk.

  • Disconnect suspicious devices – If an external drive, accessory or other connected device seems to be the culprit, disconnect it.

  • Reset network settings – This will wipe any network info like WiFi passwords stored by malware.

  • Remove unauthorized accounts – Check your app accounts for any you don‘t recognize linked to malware and remove them.

If you try these steps first and the infection persists, proceed to the nuclear option of a full factory reset. But you may be able to resolve it without nuking your phone from orbit.

If you do need to factory reset your Android device to eliminate a stubborn virus, here is exactly how to do it.

Important: Back up any data and files you need before starting the reset process, because everything will be deleted!

  1. Open your Settings app
  2. Tap System > Advanced > Reset options
  3. Select Erase all data (factory reset)
  4. Tap Erase all data
  5. If prompted, enter your PIN, pattern, or password
  6. Tap the Delete all button to confirm and begin the reset
  7. Wait for your phone to reboot – this may take several minutes

Once your phone has reset to factory settings, you can begin setting it up again from scratch. Just be sure to avoid reconnecting anything that may have been involved in spreading the prior virus!

Need to reset your iPhone or iPad to wipe out a pesky virus? Here are the steps:

  1. Open the Settings app
  2. Scroll down and tap General
  3. Choose Reset
  4. Select Erase All Content and Settings
  5. Enter your passcode if asked
  6. Tap the red Erase [device name] button to confirm
  7. Wait for the reset to complete

This will return your iPhone to factory fresh condition. Remember to backup your data first!

You will need to re-pair any Apple Watches and other devices to your iPhone after resetting, since it breaks existing pairings.

Resetting your phone is a reliable way to remove viruses, but avoiding infections in the first place is ideal. Here are some tips to keep your smartphone virus-free:

  • Only download apps from official app stores like Google Play and the App Store. Avoid third-party stores.
  • Carefully review app ratings, reviews, and developer history before downloading
  • Don‘t sideload Android APK files from unknown sources
  • Keep your device OS and apps updated with the latest security patches
  • Never open random links in texts, social media posts, emails, etc.
  • Use a VPN when connecting to public WiFi to encrypt traffic
  • Turn on antivirus scans for new apps and files if offered by your security app
  • Avoid clicking suspicious popups that could download malware
  • Set up multi-factor authentication on important accounts for added protection

Practicing caution goes a long way in keeping your phone secure!

Still have some questions about resetting your smartphone to remove malware? Here are answers to some frequently asked questions:

How can I tell if my phone has a virus?

Warning signs include reduced battery life, sluggish performance, random crashes/freezes, strange popups, and your antivirus app detecting an infection.

Will a factory reset remove 100% of viruses?

Resets remove around 95-99% of malware but very advanced viruses may occasionally persist by hiding in clever spots like the baseband processor, firmware, or recovery partition.

Is factory resetting bad for my phone?

Not at all! Resetting is a safe procedure designed by manufacturers to wipe devices. Just be sure to backup your data first.

Do I need an antivirus app if I regularly reset my phone?

Yes, you should still have antivirus software installed to catch infections before they spread and protect you after resetting your device.

Can I just do a soft reset without losing all my data?

Soft resets that restart your operating system won‘t delete your content, but this won‘t remove persistent viruses hidden within your data.

As you can see, factory resetting your smartphone is an effective way to wipe out and remove the vast majority of viruses, usually over 95% according to statistics. By restoring your device to factory fresh settings, most any malware gets erased.

However, a small number of advanced and stealthy mobile threats know how to avoid deletion and persist through resets. While rare, these viruses can occasionally slip past a factory restore by hiding in places like recovery partitions and system-level processes most resets don‘t touch.

So ultimately a factory reset offers excellent protection against common malware, but not an absolute 100% guarantee if you are targeted by sophisticated cybercriminals employing advanced persistent mobile viruses specifically designed to evade resets. Installing trusted antivirus software and avoiding suspicious downloads is your best protection.

Hopefully this gave you a better understanding of when factory resetting can wipe viruses off your phone for good! Let me know if you have any other questions.

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Streamr Go

StreamrGo is always about privacy, specifically protecting your privacy online by increasing security and better standard privacy practices.