Suspicious Login Issues

How to Check if a Hacker Accessed Your Computer Files or OneDrive

Emma Brown Oct 10, 2026 869 views

Question details

The user wants to find out how to check if their local computer files or cloud-based OneDrive files have been compromised or accessed by unauthorized individuals.

How to Check Whether a Hacker Accessed Your Computer Files

Product: Microsoft Account and Windows Security
Device & OS: not provided
Scenario: Suspecting unauthorized access, remote tampering, or a security breach regarding personal files.
Observed behavior: Potential unauthorized remote access to local files or unusual sign-in activity on the Microsoft OneDrive account.

Before you start

If you suspect an active breach, immediately disconnect your computer from the internet to prevent further unauthorized remote access, and ensure you have access to your account recovery email or phone number on a separate, secure device.

Solution 1Recommended

Review Microsoft Account Sign-In Activity

Check your account's recent activity to identify any unfamiliar or unauthorized sign-ins to your OneDrive or Microsoft account.

If your files are stored in OneDrive, any unauthorized access would likely appear in your Microsoft account sign-in history. Microsoft logs the location, device, and time of every login attempt.

Access the activity page

Open a web browser and go to the official Microsoft activity page at https://account.live.com/activity.

Log into your account

Enter your Microsoft email and password. You may be prompted to verify your identity via a secondary email or phone number.

Review recent sign-ins

Look through the 'Recent activity' list for any unfamiliar successful sign-ins, unknown geographic locations, or unexpected security challenges. Expand any suspicious entry to see the device details and IP address.

Unsuccessful Sign-ins: Seeing unsuccessful sign-in attempts from unknown locations is common and usually means your password successfully protected your account. You only need to take immediate action if you see 'Successful sign-in' from an unrecognized device.

Solution 2

Scan Your Device for Malware and Viruses

Use built-in or trusted third-party antivirus software to detect and remove malicious software that could grant hackers remote access to your local files.

Solution 3

Secure Your Account and Revoke Remote Access

Update your security credentials and uninstall any unknown remote desktop applications to lock hackers out permanently.

Free Microsoft Office alternative

Keep Your Documents Secure Offline with WPS Office

If you are concerned about cloud account security and unauthorized access, consider using a reliable, offline-capable office suite. WPS Office is a free, lightweight alternative to Microsoft Office that allows you to easily edit, save, and encrypt your documents locally, ensuring your sensitive files stay safely on your device.

1. Download and Install: Download WPS Office from the official website and follow the lightweight installation process.
2. Open Your Documents: Open your existing Microsoft Office files directly in WPS Office without losing any formatting.
3. Encrypt Sensitive Files: Go to Menu > Document Encryption to add a secure local password to your sensitive files.

Free, fast, and lightweight office suite with a familiar user interfaceFully compatible with Microsoft Word, Excel, and PowerPoint file formatsAdvanced document encryption to password-protect your sensitive local filesRobust offline editing mode so you don't have to rely entirely on cloud storage

microsoft office alternative - wps office

Frequently Asked Questions

Can someone access my computer files without knowing my password?

Yes. If your device is infected with malware, spyware, or remote access trojans (RATs), a hacker can bypass your login screen and access your local files directly while the computer is turned on and connected to the internet.

What should I do if I find unauthorized activity on my Microsoft account?

You should immediately change your Microsoft account password and choose the option to sign out of all active sessions. Then, enable Two-Factor Authentication (2FA) using the Microsoft Authenticator app to prevent them from logging back in.

How can I prevent remote access software from running on my computer?

Regularly review your installed applications in Windows Settings, use a standard user account rather than an Administrator account for daily tasks to prevent unauthorized installations, and maintain active, updated antivirus protection.

Is it possible to password-protect individual documents on my computer?

Yes. Most modern office software, including WPS Office and Microsoft Office, includes built-in document encryption. You can set a strong password for individual Word documents, Excel spreadsheets, or PDFs to ensure they cannot be opened even if a hacker copies the file.

Microsoft Office Security Issues