Can a virus be on a external hard drive?

What is an External Hard Drive?

An external hard drive is a storage device located outside of a computer that connects through a USB cable or wireless connection (Techopedia, It provides additional storage space and serves as a physical backup for important files.

External hard drives typically consist of a standard hard disk drive fitted inside a portable enclosure. The enclosure has a USB port to connect to a computer and draw power. Most external drives use a standard hard drive, similar to what’s inside a desktop computer, just with a smaller physical size. They range from about 2.5-4 inches in length (PCMag,

The key purpose of an external hard drive is to provide extra storage space for large files like photos, videos, backups, and anything that takes up significant room. They enable transferring data between computers or simply having more space available. Many people use them to backup their computer’s internal drive in case of failure or data loss. Overall, external hard drives offer a versatile way to expand storage and protect critical files.

Common Ways Viruses Spread to External Drives

There are a few primary ways that viruses can spread to external hard drives:

Via Infected Files

One of the most common ways viruses spread is through infected files. For example, if you copy a file that contains a virus from your computer onto the external drive, the virus can then spread to the external drive. Viruses like worms are designed to spread copies of themselves, so copying an infected file spreads the infection.

Through the AutoRun Feature

External hard drives use the AutoRun feature to automatically open folders or launch programs when you connect them. This is a convenient feature, but also makes it easy for viruses to spread. If an infected drive is set to automatically open a virus file when connected, it can infect the host computer.

Via the USB Connection

When you connect an external hard drive via USB, there is a direct data connection established. This gives a virus the opportunity to spread from the external drive onto the computer itself through the open USB data pathway. So a drive that contains an infection could spread it to the computer when connected.

Citing my sources:

“It is extremely unlikely for a virus to physically damage a hard disk. Hard disks can normally only be physically damaged by a physical impact …” (Source)

“Besides, plugging an infected external hard drive into your computer will most likely infect the computer and spread the virus attack into your …” (Source)

Signs of a Virus on an External Hard Drive

There are several signs that could indicate your external hard drive has been infected by a virus:

Slow performance – If you notice your external hard drive operating much slower than usual or taking a long time to open files, it may have a virus. Viruses can slow down hard drives by taking up processing power and overworking the drive.

Corrupted files – Viruses can damage and corrupt files stored on an external drive. You may get errors when trying to open files or find files that are suddenly unusable. Corrupted files, especially critical system files, point to a potential virus.

Popups – Some viruses will cause pop-up ads or unwanted windows to constantly appear when the infected external drive is plugged in. Malware likes to bombard users with popups to promote sketchy sites.

According to Microsoft, other signs can include files going missing from the external drive, strange new files appearing, and the external drive disconnecting unexpectedly. Your antivirus software may also detect a threat on the external drive and notify you of infection.

Potential Consequences of a Virus

A virus on an external hard drive can lead to several serious consequences that can compromise your data, identity, and computer system. Some of the most notable potential consequences include:

Data Loss

One of the biggest risks of a virus on an external drive is potential data loss or corruption. Viruses may encrypt files, making them inaccessible, or delete or overwrite data. According to a Quora thread, entire partitions or storage devices could be reformatted or wiped by certain viruses. This could result in irrecoverable data loss.

Identity Theft

Viruses may also target sensitive personal data stored on external drives, such as financial information, passwords, ortax documents. By transmitting this data to hackers, a virus could enable cybercriminals to steal identities or commit fraud.

System Compromise

Furthermore, if an infected external drive is connected to a computer, viruses could spread to infect the system. This could allow perpetrators to access, corrupt, or destroy data on the computer. Viruses may also use your computer resources to propagate malware, launch attacks, or mine cryptocurrency without your consent.

How to Prevent Viruses on External Drives

There are several steps you can take to help prevent viruses from infecting your external hard drive:

Update Antivirus Software – Make sure any antivirus software on your computer is up-to-date and set to scan external drives automatically when connected. Antivirus software can detect and remove many viruses before they have a chance to infect your drive. Popular antivirus software options include Avast, AVG, and Malwarebytes.

Avoid Suspicious Links – Be cautious when downloading files from the internet, especially from websites or sources you don’t fully trust. Many viruses spread through malicious downloads disguised as legitimate files. It’s best not to open unsolicited email attachments as they can contain viruses.

Regularly Scan Your Drive – Get in the habit of performing regular scans with your antivirus software, even when you aren’t actively using your external hard drive. This can help detect and remove any dormant or hidden viruses before serious infection occurs. External drives should be scanned at least weekly.

Safely Eject Drives – Always use the “Safely Remove Hardware” option to disconnect your external drive from your computer. Improper drive removal while files are still in use can lead to corruption, increasing the changes of virus infection. Ejecting properly closes any open files first.

Limit File Sharing – Be wary of file sharing sites, peer-to-peer networks, and torrent platforms. Downloads from these sources have a higher risk of containing infected files. It’s best to avoid them unless you can verify the file’s legitimacy.

How to Remove a Virus from an External Drive

If your external hard drive has been infected by a virus, there are a few methods you can try to remove it:

Run an antivirus scan

One of the best ways to remove a virus is to use antivirus software. Connect the infected external drive to your computer and perform a full scan using your antivirus program. The antivirus should be able to detect and quarantine any infected files. Make sure to update your antivirus program first to ensure it has the latest virus definitions before running a scan. Popular antivirus tools like Avast, AVG and Malwarebytes may be able to clean infected external drives 1.

Format the external drive

If an antivirus scan fails to remove the virus, you may need to format the external hard drive. Formatting will completely erase all data on the drive, removing any traces of the virus. Be sure to back up any important files and folders from the external drive before formatting it. Popular operating systems like Windows, Mac OS X and Linux provide options to quickly format an external drive.

Reinstall the operating system

A very persistent virus infection may require fully reformatting and reinstalling the operating system on the external hard drive. This process will completely wipe the drive and install a clean OS, eliminating any viruses. However, reinstalling the OS is time consuming and will erase all programs and data on the drive. Be sure to exhaust other options before performing a full reinstall.

With proper precautions, an infected external hard drive can be disinfected without losing important files and information. Rely on modern antivirus tools, formatting options, and OS reinstallation procedures to remove viruses from external drives.

Protecting Your Data and Identity

Protecting your data and identity when using external hard drives is crucial. Here are some best practices:

Back up your data regularly. Consider using cloud storage or a secondary physical drive to create backups of your external drive. Backups ensure you won’t lose important files if your drive becomes corrupted or infected. According to Super User, keeping regular backups is key to protecting your data.

Enable encryption on your external drive. Encryption scrambles your files so they can only be accessed with a password or key. This prevents unauthorized access to sensitive data. Tools like BitLocker on Windows or FileVault on Mac can encrypt external drives. As an expert on Quora recommends, encryption helps secure external drives.

Use strong passwords and multi-factor authentication. Complex passwords keep prying eyes out. Enable two-factor authentication on accounts to add an extra layer of security. Weak credentials put your data at risk.

Overall, taking preventative measures like backups, encryption and strong passwords will help safeguard your data and identity when using an external hard drive.

When to Seek Professional Help

If you’ve tried to remove the virus yourself using anti-virus software or other DIY methods, but the virus keeps coming back or your system remains infected, it’s a sign you may need professional assistance. Viruses can sometimes embed themselves deep in the operating system where they’re difficult to fully remove without specialized tools and expertise.

According to PC Geeks, “Reputable virus removal services employ technicians who possess extensive knowledge and experience in dealing with malware threats. By utilizing their expertise, they can help disinfect your device and restore it to a clean state.”

You should also seek professional virus removal help if you have valuable or sensitive data on the infected external drive that you cannot afford to lose. Professionals have the best chance of removing the virus while preserving your important files and documents. They have the skills and software to safely repair infected drives.

As Mobile PC Medics advises, “Putting your most valuable asset (your data) in the hands of a seasoned professional simply makes sense when debilitating malware strikes.” Trust the job to experts rather than risk permanent data loss or identity theft.

Alternatives to External Hard Drives

While external hard drives are convenient for transporting and backing up large amounts of data, there are other options that serve similar purposes. Here are some of the top alternatives to using an external drive:

Cloud Storage – Services like Dropbox, Google Drive, Microsoft OneDrive, and iCloud provide abundant online storage accessible from any device. Cloud storage offers more flexibility than external drives in terms of accessing files from anywhere with an internet connection. However, transfer speeds may be slower than a directly connected drive.

NAS (Network Attached Storage) – A NAS is an external hard drive that connects directly to your home or office network, allowing multiple users and devices to access and share files. NAS devices offer ample capacity and built-in redundancy to protect against drive failure. But they lack portability and require setup and management.

Internal Drives – Adding an extra internal drive to a desktop PC or laptop is simpler than managing an external drive. But internal drives make transferring files between devices more difficult. Large-capacity internal drives can also be more expensive than external drives.

For transportability, external SSDs provide faster transfer speeds and more durability than mechanical hard drives. But with higher costs per gigabyte, SSDs generally offer less storage capacity for the price.

The right drive solution depends on your budget, usage needs, and preference for accessibility, portability, or redundancy. While external hard drives remain popular, the expanding range of alternatives provides more choice than ever.


As we’ve covered, external hard drives are convenient for storing and transporting data, but like any storage device they’re vulnerable to malware infection. Viruses can spread through unsafe browsing, infected files, or autoplay. Signs of infection include strange behavior, poor performance, and antivirus alerts.

While a virus won’t directly damage the hardware, it can corrupt, delete or encrypt your files. To avoid this threat, practice safe computing habits, scan devices regularly, and don’t open suspicious files. If an infection occurs, antivirus software can often clean it. For severe cases, reformatting may be required.

In summary, viruses on external drives are preventable and treatable with vigilance. Keep backups, use malware protection, and avoid questionable sources. Handle portable drives with care, and they’ll serve you well as a reliable data storage and transfer solution.