How to Fix Partition Failed Error in Mac?

When the amount of data is increased, you need to enlarge the data storage capacity of your Mac machine by purchasing a new hard drive with its size greater than that of the previous one. When you purchase a new hard drive (whether internal or external), the whole memory is assigned as a single partition. Therefore, you need to partition Mac drive into required number of volumes in order to save different type of data separately. Your data can be anything like, audio and video files, professional documents, software, personal collection of pictures, etc. Most importantly, the operating system installation requires a separate volume.

For resolving partitioning & formatting issues on Macintosh hard drives, we recommend use of this disk manager utility.

Sometimes, it is seen that people install operating system on a hard drive without partitioning. In this situation, they have to repartition the same hard drive when more data is to be stored. Disk Utility in Mac operating systems allows splitting the hard drive into several volumes anytime (during and even after OS installation) without data loss. However, people have been notifying about a “Partition Failed” error in Mac that is encountered while attempting to repartition the hard drive. This error displays a message that states:

“Couldn’t modify partition map because file system verification failed.”

Therefore, it is necessary to follow precautionary steps to resize the hard drive with single partition and to create a new one.

• Launch to Disk Utility (Applications-> Utilities folder-> Disk Utility).
• In the left pane, select the target hard drive, and simultaneously go to the Partition tab in the right pane.
• Under Partition Layout area, click the graphical structure of the hard drive.
• Click and hold the bottom-right corner (where you can see three diagonal lines) of the drive structure, and drag the partition upward for shrinking its size.

(You can resize an existing Mac partition only if the hard drive is using GUID Partition Table as the Partition Map Scheme. Therefore, before attempting to resize it, first make sure the Partition Map Scheme used by the hard drive is GUID Partition Table; check it under First Aid tab.)

If hard drive throws a “Partition Failed” error, then move to Single User Mode and follow the steps mentioned below.

• Restart the Mac, immediately press and hold Command + S keys to boot in Single-user mode.
• In the command prompt, run the command: /sbin/fsck/ -fy
• When the process is finished, type exit and reboot normally.
• Launch Disk Utility, Select the Disk and click ‘Verify Disk’.

Now, again go to the Partition tab and try to partition Mac drive normally. Drag the existing partition upward to trim some free space from it. Now, use the trimmed space to create another Mac volume. Under Volume Information area, specify a Name, choose a file system Format, and size for the newly created partition. It is recommended to choose Mac OS Extended (Journaled) format as the file system format for the volume to make it boot enabled.