Removing the soundhw hda device prevents the deadlock.
Below was my QEmu start-up command-line:
qemu-system-x86_64 \
-enable-kvm \
-m 8192 \
-drive if=pflash,format=raw,readonly,file=./ovmf-x64/OVMF-pure-efi.fd \
-drive if=pflash,format=raw,file=./OVMF-pure-efi-Win10.fd \
-drive file=/dev/Stuff/W
Public bug reported:
I was able to install and can log in but whenever a pop-up is attempted the VM
appears to deadlock.
I can still kill -9 the process and recover but the VM and the QEmu console
both hang with no error output.
At first I thought it was UAC but renaming a file causes a pop-up
