I'm using what could be considered a "hack" of sorts to use a Bootcamp partition on an external SSD via USB rather than from my Mac's internal drive. This is done in line with the below guide:
https://egpu.io/forums/mac-setup/how-to-install-windows-10-bootcamp-on-an-external-hdd-or-ssd/
It basically involves creating a GPT partition scheme to create a small EFI partition in FAT32, then creating a 2nd partition in NTFS. Windows is installed via DISM on the NTFS partition which basically burns a bootable image of windows to the partition versus going through an installer.
This works fine with native bootcamp if you hold down the option key at boot and select the EFI partition as the boot disk. It also worked fine in parallels desktop 12 -- I would select add new hard drive, select bootcamp, and then choose my external SSD from the list. For this hack to work, I would then need to select both the EFI boot partition and main windows partition and Parallels could load my external windows installation just fine.
Parallels 13, by comparison, does some weird thing where if I try to add the external disk as a bootcamp drive, it claims the .HDD file its trying to create has some read/write error. If I click for more detailed info, it just states "PRL_ERR_DISK_PARTITION_NOT_FOUND" -- an error string that has 0 hits on Google or this site. I've uninstalled any 3rd party apps that could affect filesystem access, including Paragon NTFS.
I cannot collect any other logs at this time as I have since rolled back to parallels desktop 12 which is working fine again with the external drive.
https://egpu.io/forums/mac-setup/how-to-install-windows-10-bootcamp-on-an-external-hdd-or-ssd/
It basically involves creating a GPT partition scheme to create a small EFI partition in FAT32, then creating a 2nd partition in NTFS. Windows is installed via DISM on the NTFS partition which basically burns a bootable image of windows to the partition versus going through an installer.
This works fine with native bootcamp if you hold down the option key at boot and select the EFI partition as the boot disk. It also worked fine in parallels desktop 12 -- I would select add new hard drive, select bootcamp, and then choose my external SSD from the list. For this hack to work, I would then need to select both the EFI boot partition and main windows partition and Parallels could load my external windows installation just fine.
Parallels 13, by comparison, does some weird thing where if I try to add the external disk as a bootcamp drive, it claims the .HDD file its trying to create has some read/write error. If I click for more detailed info, it just states "PRL_ERR_DISK_PARTITION_NOT_FOUND" -- an error string that has 0 hits on Google or this site. I've uninstalled any 3rd party apps that could affect filesystem access, including Paragon NTFS.
I cannot collect any other logs at this time as I have since rolled back to parallels desktop 12 which is working fine again with the external drive.