Boot Camp in Fusion 8.5.10 under macOS 10.13 "High Sierra"
I upgraded to macOS 10.13, "High Sierra", but I'm stuck with Fusion Pro 8.5 because my machine does not support Fusion Pro 10. My "standard" VMs seem to work OK, but I need to use my Boot Camp partition too. Trying to start the machine gives the message: "Operation not permitted: Cannot open the disk '/Users/keller/Library/Application Support/VMware Fusion/Virtual Machines/Boot Camp/Boot Camp.vmwarevm/Boot Camp.vmdk' or one of the snapshot disks it depends on. Module 'Disk' power on failed. Failed to start the virtual machine."
The conclusion of this thread is rather laconic: can't be done. This thread, however, provides a little more information: the basic problem is that the BIOS boot data can't be read from the boot disk when System Integrity Protection (SIP) is enabled; it then shows how to fix the problem for Fusion 10. I successfully used this fix for Fusion 10 on my other machine; so I thought, what the heck, maybe a similar fix works for Fusion 8.5. I have verified that Boot Camp does indeed boot within Fusion when SIP is disabled. However, the patch to the "Boot Camp.vmdk" file (last paragraph of the fix) does not work.
Does anyone understand enough of this file and the Windows boot process to figure out what the patch is doing? I imagine that the fix copies the BIOS boot data to somewhere accessible even when SIP is enabled; and I also found this document about the structure of the .vfx file. But I'm missing the know-how to imagine a fix – or to know whether it's possible.
You're going to be at high risk of corruption. At the very least I'd move away from Boot Camp and run a traditional VM until you can upgrade the hardware to a supported platform. I'm surprised that you can run High Sierra and not run Fusion 10 - I thought the two were aligned.