copied Bootcamp Partition to external drive. cant boot on other mbp

slvrscoobie

macrumors 6502a
Original poster
Mar 24, 2013
588
132
NJ
I have 2 macbook pro, a 2012 and a 2018. I installed Windows very easily on the Catalina 2012 MBP and can switch seemlessly. but if I need windows for work i need to bring the 2nd computer with me, which can be annoying.
I thought If i could put it on an external like i did with VirtualBox before bootcamp, it would run on my 2018 mbp, both my work and personal machines! Wunderbar!
so I used diskutil to restore the SSD from the internal BOOTCAMP partition.
the 2012 macbook pro boots, and I can select either Bootcamp partition (internal or external) as well as Catalina.
my 2018 doesnt show it at all. I went to recovery mode last night (to enable booting from external drives) and it DID show it in 'start up disk options' but when i selected it, it said it was not blessed and could not be booted.
Am I missing something?
I tried to just install Bootcamp on that computer, but it failed the install and froze, so i decided to just wipe it.
 

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Quackers

macrumors 6502a
Sep 18, 2013
646
1
Manchester, UK
I'm definitely no expert and I've forgotten more about this stuff than I currently know, however from what I can remember I think Windows has a problem booting from an external drive. And a copied version would have even more difficulty I suspect. Especially as you may have no boot files present if you only copied the Windows partition.