How to lock a folder in external hard drive for Windows PC?

Use Windows Built-in File Permissions (Basic Security) to lock a folder in external hard drive. It uses NTFS permissions to control who can access the folder. However, it has limitations:

• Only works if the external drive is formatted as NTFS.
• Doesn’t encrypt files (less secure than BitLocker).
• Permissions can be bypassed if someone takes ownership or accesses the drive from another OS.

Steps:

1. Right-click the folder > Properties > Security tab.

2. Click Edit > Deny permissions for all users except yourself.

3. Click Apply > OK. This will lock a folder in external hard drive on any Windows OS.

Limitations & Workarounds

1. Doesn’t work on FAT32/exFAT: Must use NTFS.

2. Bypassable via Linux/macOS: NTFS permissions don’t apply outside Windows.

3. "Access Denied" even for you? Fix: Take ownership via:

Right-click folder > Properties > Security > Advanced.

Next to Owner, click Change > Type your username > OK.

Check "Replace owner on subcontainers and objects" > Apply.