How to encrypt, password protect external hard drive for Mac & Windows PC usage?

Updated by Tim to BitLocker for Mac on April 7th, 2021

How to format external hard drive for Mac and Windows PC usage?

1. Format external hard drive to FAT32/exFAT file system.

Although FAT32/exFAT file system is developed by Microsoft, but macOS can also read/write external hard drive with FAT32/exFAT file system.

2. Format external hard drive to NTFS file system.

Although NTFS file system is developed by Microsoft, but macOS can only read NTFS external hard drive and cannot write NTFS external hard drive, you need to install extra NTFS for Mac app if you want to write NTFS external hard drive on Mac.

How to password protect external hard drive for Mac and Windows PC usage?

As far as we know, there are many cross platform encryption solutions (such as TrueCrypt), but BitLocker is more secure than other drive encryption software. Although Microsoft just developed and released BitLocker for Windows and there's no Mac implementation, but with the help of M3 BitLocker Loader for Mac, BitLocker encrypted external hard drive can be readable on Mac.

Tutorial to encrypt external hard drive with BitLocker on Windows

Step 1: Insert external hard drive to a Windows computer.

Windows 10 Professional/Enterprise, Windows 8/8.1 Professional/Enterprise, Windows 7 Ultimate/Enterprise, Windows Vista Ultimate/Enterprise, Windows Server 2008/2012 are available for BitLocker drive encryption.

Step 2: Format external hard drive into FAT32/NTFS/exFAT file system. If there is data in external hard drive, please go to step 3.

Step 3: Right click external hard drive in My Computer or This PC and select "Turn on BitLocker".

Step 4: On the "Choose How You Want To Unlock This Drive" window, choose "Use A Password To Unlock This Drive" option and then click Next.

Step 5: On the "How Do You Want To Store Your Recovery Key" window, click Save The Recovery Key To A File.

Step 6: In the "Save BitLocker Recovery Key As" window, choose a storage location and then click Save.

Step 7: On the "Are You Ready To Encrypt This Drive" window, click Start Encrypting.

Tutorial to encrypt external hard drive with BitLocker on Mac

Step 1: Download and install M3 BitLocker Loader for Mac.

Step 2: Insert an external hard drive into Mac computer.

Step 3: Launch M3 BitLocker Loader for Mac.

Step 4: Click "Encrypt" button in toolbar.

M3 BitLocker Loader for Mac

Step 5: Select the partition which you want to encrypt and click Encrypt.

Encrypt drive with M3 BitLocker Loader for Mac

Step 6: Enter the password.

Step 7: Save the recovery key.

Step 8: Complete BitLocker drive encryption.

After encrypting, you can use M3 BitLocker Loader for Mac to open BitLocker encrypted drive on Mac and then read/write this drive as same as your Mac's native drive.