Your Mac will restart several times during the process. Click either Windows 10 Pro or Windows 10 Pro based on your preference.Type your product key or click I don't have a key.There is no way to select the boot drive. In other words, when specifying the the legacy boot option, the firmware tries to BIOS boot. I believe the -device /dev/disk3s1 is a dummy option which is ignored. sudo bless -device /dev/disk3s1 -setBoot -legacy Your question included the command which is repeated below. Windows on the USB drive may be detected and included in a Windows boot manager.Ī final note. Since you have Windows already installed on the internal drive, try rebuilding the BCD on the internal drive. You would have to try this on your Mac to see if it would work.Īnother option would be the following. I have never tested such an arrangement to see if it would work with any Mac model. The System and Windows partitions are described in the Microsoft document BIOS/MBR-based hard drive partitions. One possible way to come close to having Windows on an USB drive would be to put the System partition on the internal drive and Windows partition on the USB drive. For example, see the question Bootcamp “Missing Operating System” on external drive. However, some (if not all) of the very next year MacBook Pro models can BIOS boot from USB. So your model probably can not BIOS boot from USB. In 2015, Apple started to eliminate the ability to BIOS boot entirely, which effectively ended the ability to install Windows 7. This continued through at least the 2014 model year. However, since Windows 7 required a BIOS boot, Apple started adding the ability to BIOS boot from USB. This is also the time Apple starting to eliminate the optical drives from Mac models. Apple did not catch up until around 2012/2013. The industry switched to EFI booting of Windows in 2011. Your Mac is probably just a year to early. UPD: I've noticed that my USB drive is detected as internal, that's not true. Here's my partition table: /dev/disk0 (internal, physical):ģ: Microsoft Basic Data BOOTCAMP 119.9 GB disk0s3Ģ: Apple_APFS Container disk2 127.8 GB disk1s2Ġ: APFS Container Scheme - +127.8 GB disk2ġ: APFS Volume w32u SSD - Data 11.0 GB disk2s1Ġ: FDisk_partition_scheme *125.1 GB disk3Ĭan I actually boot from USB with the MBR bootloader on Mac or not? I've tried any way, including rEFInd, but it results again in booting to Win10 installed on disk0 HDD. It doesn't work – it just boots to Windows 10 installed on the internal HDD with legacy method + Hybrid MBR too. When I'm trying to boot from the USB with the command (I've unmounted the disk before): sudo bless -device /dev/disk3s1 -setBoot -legacy For experimental purposes I've installed Windows 7 to USB (it's NOT an installer, a real OS on USB) via WinNTSetup on other PC.

Booting windows on mac