Boot camp assIst InstallatIon failed
an error occurred whIle copyIng the WIndows InstallatIon fIles....................................................................

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when I was installing win 11 it gave me the same problem again( despite of Original ISO)..but when I upgraded from sierra to mac Mojave it worked..... :) looks like it formated the old mac and old win 10

And Win 11 TMP prob solved by the below link.
   • Fix: This PC can't run Windows 11 (By...  


For Win 10
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The problem was with the ISO file, once i download the original ISO from the Microsoft website it worked.
Instruction for downloading ISO: https://www.tenforums.com/tutorIals/9...
Microsoft website to download ISO :
https://www.mIcrosoft.com/enIn/softw...