Not sure if this is even possible, but I have a 2019 iMac which I'm booting from an external SSD (quicker than the internal fusion drive)
As the fusion drive isn't used for much, I'd like to install Win 10 on it using bootcamp, but the assistant throws up an "external storage device attached" message up as soon as it starts and won't go any further...
Any pointers appreciated!
iMac 27", macOS 10.15
MikeLJ99 wrote:
I think what I'm trying to understand - if I remove the external SSD, boot the Mac to the Fusion drive, run Bootcamp and install Win 10 to the Fusion drive,
Yes, this is the normal method of Windows installation. I will assume that you have macOS installed on the internal Fusion drive.
can I then reattach the external SSD & still boot from it...? All I want is to be able to either boot MacOS from the external SSD, or Win 10 from the Fusion drive
Yes, after you install W10 on the internal Fusion drive, you can boot from any of the following.
MikeLJ99 wrote:
I think what I'm trying to understand - if I remove the external SSD, boot the Mac to the Fusion drive, run Bootcamp and install Win 10 to the Fusion drive,
Yes, this is the normal method of Windows installation. I will assume that you have macOS installed on the internal Fusion drive.
can I then reattach the external SSD & still boot from it...? All I want is to be able to either boot MacOS from the external SSD, or Win 10 from the Fusion drive
Yes, after you install W10 on the internal Fusion drive, you can boot from any of the following.
Do you have a macOS installation on the internal Fusion drive? Is your internal Fusion drive split?
There should be a single APFS container, but should have multiple APFS volumes. From macOS Terminal, post the output of
diskutil list
diskutil apfs list
You may have APFS corruption. Can you post the output of
diskutil list
Didn't work unfortunately.
Removed external SSD.
Wiped internal fusion drive and reinstalled fresh copy & updated Catalina
Bootcamp assistant then reported unable to partition drive. Restarted in recovery mode, ran disk utility first aid. Rebooted. No difference.
Any thoughts ?
Thks
I think what I'm trying to understand - if I remove the external SSD, boot the Mac to the Fusion drive, run Bootcamp and install Win 10 to the Fusion drive, can I then reattach the external SSD & still boot from it...? All I want is to be able to either boot MacOS from the external SSD, or Win 10 from the Fusion drive
Cheers
Hi - yes, Catalina installed on the internal drive but I don't use it....disk utility shows that drive having two containers (?) - Mac HD and Mac HD - Data
thks
Sorry yes single container, 2 x volumes
Will give it a go!
thanks for your help
On a Fusion drive, the Windows installation is on the 'HDD' part of the Fusion drive. The SSD part and some part of the HDD of is designed to be used exclusively by macOS. There should be no external storage connected to 2015 or later Macs during Windows installation.
Using bootcamp to install Win 10 on second drive
