5 signs your home computer may be hacked
Whether you have a Mac or PC at home, it’s easier than ever for your device to be compromised. Here are some easy ways to check.
Cybercriminals don’t need to break into your house to wreak havoc — they can do it from anywhere in the world. If your computer is acting strangely, don’t ignore it. Check these 5 signs your PC or Mac has been hacked or compromised.
If your home computer is running slowly, it can be due to age or it could be a malicious compromise. Here’s how to check.
your antivirus software has been disabled
Antivirus software isn’t the ‘safety net’ it used to be. Most modern devices have it included for free (as do Android and iPhone devices).
Having antivirus installed does not protect against all threats- follow the ASD's ACSC’s guidance to understand good home security habits to protect and secure yourself while browsing online.
Saying that, if your installed antivirus is disabled, it can be a sign of compromise.
FOR PC: Go to Start > Settings > Privacy & Security > Windows Security > Virus & threat protection.
Check if Microsoft Defender (or your antivirus) is running.
If it’s off and you didn’t disable it, malware may be trying to avoid detection.
FOR MAC: Open your third-party antivirus app (if installed) from the Applications folder.
If you rely on built-in Mac security, confirm system settings haven't changed in System Settings > Privacy & Security.
🛠 How to fix:
Reinstall or re-enable your antivirus.
If blocked, reboot in Safe Mode (PC: hold Shift on restart; Mac: hold Power button + Shift).
Run a full scan.
2. new or strange programs and files show up
A computer infected with malware can install and run software designed to steal online account details without the user’s permission.
You might also notice new files appearing in your Downloads or Documents folders that you didn’t create.Personal transaction accounts are one of the most common payment methods scammers use.
FOR PC: Check installed apps in Settings > Apps > Installed Apps.
Use Task Manager (Ctrl + Shift + Esc) to see unfamiliar processes using high resources.
FOR MAC: Look under Finder > Applications for new or unknown apps.
Use Activity Monitor (Finder > Applications > Utilities) to investigate suspicious activity.
🛠 HOW TO FIX
Google any unfamiliar app or process before deleting.
Uninstall or drag to Trash as needed.
Don’t ignore strange files in Downloads, Documents, or on your desktop. Call in a professional if you need.
Avoid using public computers or WiFi hotspots to access or provide personal information.
Choose passwords and PINs that would be difficult for others to guess, and update them regularly. Do not save them on your phone or computer in the browser, even if it’s convenient.
Do not open attachments or click on links in emails or social media messages you’ve received from strangers – just press delete.
Be wary of free downloads and website access, such as music, games, movies and adult sites. They may install harmful programs without you knowing.
Do not use software that auto-completes online forms.
3. Suspicious Logins or Alerts on Your Online Accounts
Your online subscription services — such as email, social media or accounting softwre— will alert you if they detect suspicious activity or a login on your account.
You have to be doubly careful that these email or text alerts are NOT phishing messages or recovery scammers.
These messages might alert you to access from an unfamiliar device or location, like another country. These warnings CAN be from scammers or CAN ALSO be a sign that someone has used stolen login details, possibly obtained through a data breach or malware on your computer.
🛠 HOW TO FIX
If you receive an unexpected alert, it could mean your PC or Mac has been compromised and your personal credentials have been exposed. It can also mean scammers are sending you phishing emails to click on malicious links.
Change your passwords immediately (this gets tricky so paid and free password lockers like LastPass or 1Password are useful)
Use strong, unique passwords for each account.
Enable Two-Factor Authentication (2FA).
Check your account’s login history (Google, Apple, Microsoft, etc.).
Use tools like haveibeenpwned.com
to check if your data has been leaked.
Beware of fake email alerts pretending to be from your bank or service provider.
4. your Computer Is Slower Than Usual
Sudden sluggishness may mean malware is running in the background.
FOR PC/WINDOWS: Open Task Manager and look under the Processes tab.
Sort by CPU or Memory to identify suspicious activity.
FOR MAC: Open Activity Monitor.
Check the CPU or Memory tabs for high-resource usage from unknown sources.
🛠 HOW TO FIX
Run a full antivirus or anti-malware scan.
Avoid quitting processes unless you're sure what they are.
Clear up storage space if you’re running low.
5. Your default Browser Has Changed Without Your Permission
A common sign of malware or adware infection is a hijacked browser.
FOR PC/WINDOWS: Chrome: Go to Settings > Search Engine and check your default engine.
Edge: Go to Settings > Privacy, Search, and Services.
Remove unfamiliar extensions: Settings > Extensions.
FOR MAC: Safari: Settings > General to check homepage; Settings > Extensions to review add-ons.
Chrome: Follow the same steps as on Windows.
🛠 HOW TO FIX
Reset your homepage and search engine.
Delete suspicious extensions.
Run a virus scan to clean up any adware.