NTFS (NT File System) is the default file system for Windows operating systems. It supports advanced storage features like encryption and disk quotas. However, Macs do not support writing to NTFS drives by default.
Macs use HFS+ or APFS formats. These formats allow full read/write support on Mac but cannot be directly written to from Windows. When switching a hard drive from Windows to Mac it is necessary to convert the format.
This guide will walk through the steps to convert a hard drive from NTFS to a Mac compatible format without losing data. The process involves backing up the data, converting to an interim format, transferring data to the Mac, reformatting to HFS+ or APFS, transferring data back, and verifying the results.
Properly following these steps will enable use of the hard drive on MacOS while preserving the existing data from the Windows NTFS volume.
Back Up Your Data
Before changing the file system format of your hard drive, it is absolutely critical that you create a complete backup of all your data. Loss of data is a significant risk any time you reformat a disk. Following best practices for backups will help ensure no important files are lost in the process.
Experts recommend following the 3-2-1 backup rule: maintain at least 3 copies of your data, store backups on 2 different media types, and keep 1 backup copy offsite or in cloud storage. For a full disk backup, use disk imaging software to make an exact copy of the entire drive rather than just copying individual files.
Invest in a high-quality external hard drive with at least 2-3 times the capacity of your computer’s internal drive [1]. USB flash drives and optical discs may also be used for backups, but have more limited capacity. Online backup services provide offsite storage and automatic syncing for convenience, though initial uploads may take time [2].
With a complete, recent backup available, you can proceed with reformatting your drive while minimizing risk of data loss. Be sure to clearly label backups and verify they contain all needed files before erasing or reformatting the original disk.
Check Your Hard Drive’s Partition Scheme
Before converting the hard drive, you need to check whether it uses the Master Boot Record (MBR) or GUID Partition Table (GPT) partitioning scheme. This will determine the steps required to reformat it for Mac OS.
The MBR partitioning method has been around since the early days of DOS and Windows. It uses a legacy boot sector to store information about partitions. However, MBR has limitations – it can only support up to 4 primary partitions and 2TB maximum partition size (source).
GPT is a newer standard introduced with UEFI firmware that lifts these restrictions. It stores more redundant partition data for added robustness. GPT allows for unlimited partitions and 9.4ZB maximum partition size. It also provides better support for bootable partitions above 2TB (source).
To check your drive’s partitioning scheme on Windows, go to Disk Management. Right click the disk and select Properties. Look at the Partition style field to see if it says MBR or GPT (source). This will determine the steps needed to reformat it for Mac.
Convert to ExFAT
exFAT is an interchange format that can be read and written to by both Windows (NTFS) and Mac (Mac OS Extended). Converting the drive from NTFS to exFAT ensures compatibility with both operating systems without data loss. Here are the steps to convert an NTFS drive to exFAT:
1. Back up any important data on the drive as a precautionary measure. Use backup software or copy files manually to a separate storage device.
2. In Windows, open Disk Management. Right click on the NTFS partition you want to convert and select “Format”.
3. Under “File System”, choose “exFAT” from the dropdown menu. Make sure the “Quick Format” box is checked for a faster format.
4. Click “OK” to format the partition to exFAT. This will remove all data but now the drive can be used interchangeably between Windows and Mac.
According to Difference between exFAT and NTFS, some advantages of exFAT over NTFS include the ability to restore accidentally deleted files and restore formatted partitions. The tradeoffs are lack of compression and permissions. But for transfer between Windows and Mac, exFAT is the preferred common format.
Transfer Data to Mac
Once the external hard drive has been formatted to exFAT, you can connect it to your Mac and transfer the data over. Here are the steps:
- Connect the external hard drive to your Mac using a USB cable.
- Open Finder and locate the external hard drive under Devices on the left sidebar.
- Open a new Finder window and navigate to the location of the files you want to transfer. This is likely your Windows user account folder if transferring from a Bootcamp partition.
- Select the files and folders you want to move and drag them over to the external hard drive volume.
- The files will begin copying over. Let the transfer complete.
- Eject the external drive once the copy is finished.
The exFAT format allows the drive to be read and written to by both Windows and macOS. So you can directly connect the exFAT external drive to your Mac and transfer files between the two operating systems. Just connect the drive, locate it in Finder, and drag-and-drop to move files over.Apple Support provides step-by-step instructions on using Migration Assistant to transfer files as well.
Format Drive to Mac OS Extended
Once you have transferred all the data you want to keep to your Mac, you can format the external hard drive to Mac OS Extended (also known as HFS+) file system. This will allow the drive to be fully compatible with Mac computers.
To format the drive on a Mac:
- Open Disk Utility on your Mac (located in Applications > Utilities)
- Select the external hard drive from the left sidebar
- Click “Erase” at the top
- Choose “Mac OS Extended (Journaled)” as the format
- Type a name for the drive
- Click “Erase”
This will permanently erase all data on the drive and format it to HFS+. Be absolutely certain you have backed up all the data you want to keep before erasing the drive.
Once formatted to HFS+, the external hard drive will be fully optimized for usage with Mac computers. You can then transfer data back to the drive.
Transfer Data Back
After formatting the external hard drive to Mac OS Extended (HFS+), you’ll need to transfer your files back from the Mac onto the external drive.
Here are the steps to move files from your Mac back to the newly formatted HFS+ external hard drive:
- Connect the external hard drive to your Mac via USB port.
- Open Finder and locate the files you want to move back to the external drive. They may be on your desktop, documents folder or another location.
- Select the files and folders you want to move.
- Drag and drop the selected files/folders onto the external hard drive icon in Finder.
- Alternatively, you can use Copy and Paste to move files – select files, press Command+C to copy, then Command+V to paste onto the external drive.
- The files will begin copying onto the external drive.
- Wait for the copy process to complete. The status will be displayed in Finder.
- Eject the external hard drive safely once done.
Now your files should be transferred back to the external hard drive freshly formatted to work with Mac OS X. You can access them like before.
Check and Verify
Verifying the integrity of your files after transferring them is a crucial step. It ensures that no errors occurred during the transfer process and that your files are exactly the same as the originals. As this article points out, checking file integrity protects against data corruption, errors, and malicious tampering.
There are a few ways to check for errors and verify file integrity on Windows and Mac. A simple method is to compare the file sizes and timestamps of original files and transferred files. You can also use checksum tools like md5sum or sha256sum to generate hash values for files before and after transfer. The hash values serve as a fingerprint – if they match, the files are identical.
For extra security, use file comparison software to conduct a byte-by-byte check. This will detect even the smallest discrepancy between original and transferred files. Take the time to carefully verify your files – it’s a small price to pay for peace of mind and confidence in your important data.
Optional: Divide Into Partitions
If desired, you can divide the external hard drive into separate partitions for Mac OS and Windows after formatting it to exFAT or Mac OS Extended.
To create partitions on the drive:
- Open Disk Utility on your Mac.
- Select the external hard drive from the list on the left.
- Click the “Partition” tab.
- Click the “+” button to add a new partition.
- Select the partition scheme (GUID or MBR).
- Enter the desired size for each partition.
- Select the format for each partition (NTFS for Windows, HFS+ or APFS for Mac).
- Click “Apply” to create the partitions.
This will divide the external hard drive into separate sections that can be accessed by Mac OS and Windows. Be sure to move any data on the drive into the appropriate partitions before formatting.
For example, you could create one 500GB HFS+ partition for Time Machine backups, and leave the remaining space as NTFS for general file storage accessible by both operating systems. Just be aware of the file system limitations if sharing files between macOS and Windows.
For more details on partitioning in Disk Utility, see Apple’s support article: https://support.apple.com/guide/disk-utility/partition-a-physical-disk-dskutl1402/mac
Conclusion
In summary, to change a hard drive from NTFS to a Mac-compatible format without losing data, the key steps are:
- Back up your data to be safe
- Check your partition scheme and convert to ExFAT if needed
- Transfer data to a Mac computer
- Format the drive to Mac OS Extended
- Transfer the data back to the external drive
- Verify the data was copied correctly
- Optionally divide into partitions for both Mac and Windows
Following these steps carefully will allow you to prepare your external hard drive to work interchangeably between Windows and Mac machines. Be sure to always safely eject the drive before disconnecting it. With the drive properly formatted as ExFAT or Mac OS Extended (with a Windows partition if needed), you’ll be able to transfer files seamlessly between computers.