Make external drive Mac-only, keep Mac data?

I have a 1TB external hard drive that was originally partitioned for Mac (500gb) and Windows (500gb). I would like to have the whole drive for Mac, without having my original files on the Mac side deleted. How do I do this? I have googled this and cant seem to get a straight answer.

MacBook Pro 15″, macOS 14.5

Posted on Feb 3, 2026 7:57 AM

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Posted on Feb 3, 2026 8:48 AM

LRCreations wrote:

I have a 1TB external hard drive that was originally partitioned for Mac (500gb) and Windows (500gb). I would like to have the whole drive for Mac, without having my original files on the Mac side deleted. How do I do this? I have googled this and cant seem to get a straight answer.


Copy those Mac files off to another drive to preserve them.


erase/reformat/initialize the drive as new, using Disk Utility>View (Show All Devices) to proceed


for Mac only: GUID /APFS


Erase and reformat a storage device in Disk Utility on Mac

Erase and reformat a storage device in Disk Utility on Mac - Apple Support


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Question marked as Top-ranking reply

Feb 3, 2026 8:48 AM in response to LRCreations

LRCreations wrote:

I have a 1TB external hard drive that was originally partitioned for Mac (500gb) and Windows (500gb). I would like to have the whole drive for Mac, without having my original files on the Mac side deleted. How do I do this? I have googled this and cant seem to get a straight answer.


Copy those Mac files off to another drive to preserve them.


erase/reformat/initialize the drive as new, using Disk Utility>View (Show All Devices) to proceed


for Mac only: GUID /APFS


Erase and reformat a storage device in Disk Utility on Mac

Erase and reformat a storage device in Disk Utility on Mac - Apple Support


Feb 3, 2026 2:34 PM in response to LRCreations

If the Mac partition is the first partition on the drive, then it may be possible to delete the Windows partition & merge it back into the Mac partition. However, you want to follow @leroydouglas' suggestion to make a good backup of all the data on that drive just in case something goes wrong since modifying partitions is risky. If something goes wrong while modifying the partitions, then you may lose all of the data stored on that drive.


If the Mac partition is the 2nd partition, then you have no other option that to erase the whole drive in order to have a single partition on that drive.


FYI, people should always have frequent & regular backups of the data stored on external media (including the cloud) which contains important & unique data. And of course the main drive on the computer should also have frequent & regular backups because there are a lot more new ways to permanently lose access to the data stored on the internal SSD of the recent Macs due to all of the hardware, software, and security changes.

Feb 3, 2026 5:15 PM in response to LRCreations

Since changing the partitioning on a drive CAN lead to sudden and complete data loss on that drive, Best Practice is to have a complete backup of all the files from that drive.


And... once you have a complete backup of all the stuff on the drive, you are FAR better off just erasing the whole drive and setting it up properly, then restoring from the backup.

Make external drive Mac-only, keep Mac data?

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