macUSB

macUSB is a free, open-source utility for creating bootable macOS, Windows, and Linux installation media on a Mac. It prepares USB drives and SD cards, writes supported installer images, and includes a downloader that fetches macOS and older OS X installers directly from Apple. Its support for older macOS installers is particularly useful on Apple silicon Macs, where traditional creation methods can fail.

Create installers for macOS, Windows, and Linux

• macOS: Download available releases from Apple or use local .app, .dmg, .cdr, or .iso files. The app handles compatibility issues associated with older installers, including Catalina and earlier.
• Windows: Create installation media from supported Windows ISOs, including Windows Vista through Windows 11. Depending on the version, it supports legacy BIOS or UEFI booting and offers optional Windows 10/11 setup adjustments, such as skipping certain account and hardware checks.
• Linux: Write supported ISO images, with automatic distribution detection. A separate raw-image tool can write .iso and .img files directly to external drives.

More flexible USB and SD card preparation

Version 2.6 adds SD card support and calculates target capacity from the actual source size, with a 5% allowance, rather than always requiring at least 16 GB. For OS X Lion and newer, eligible existing HFS+ volumes can be selected without repartitioning the entire drive. Previous-session diagnostic logs can also be exported.

Requirements and important limitations

macUSB requires macOS Sonoma 14.6 or later and works on Apple silicon and Intel Macs. Creating installation media erases the selected drive, SD card, or volume, so the target must be checked carefully. The app requires Full Disk Access and Background App Activity for its privileged helper. External HDD/SSD targets are disabled by default as a precaution.

For some Windows images, the separate wimlib utility is needed to split files larger than FAT32 allows. The built-in downloader is for macOS installers; Windows and Linux images must be supplied separately. macUSB is distributed under the MIT license through GitHub Releases and Homebrew.