The following steps have been tested on macOS Mojave 10.14.6 and I confirm I was able to boot GParted on a 2019 MacBook Air (with secure boot disabled). That being said, the keyboard and trackpad didn’t work as drivers are not yet available on live distros. Also, the new T2 chip currently prevents live distros from accessing the SSD (another driver issue).
Step 1: Open Disk Utility
.
Step 2: Click on View
(upper left) and select Show All Devices
.
Step 3: Select your thumb drive and click Erase
.
Step 4: Select MS-DOS (FAT)
as Format
and GUID Partition Map
as Scheme
.
Step 5: Click Erase
.
Step 6: Download the latest gparted-live-1.0.0-3-amd64.zip.
Step 7: Double-click on gparted-live-1.0.0-3-amd64.zip
to unzip folder.
Step 8: Copy all files from gparted-live-1.0.0-3-amd64
to your thumb drive.
You now have a bootable version of GParted that should work on your Mac!