by antevans » 3. Aug 2015, 22:09
GWX refused to upgrade my Win 7 32 bit guest because it didn't like the graphics driver - see examples above. It turns out this doesn't matter - you can upgrade Windows manually. But don't make the same electron-wasting mistakes I did.
I did not have a chipset compatibility problem (PIIX3 & I/O APIC). System compatibility I set to Win 10 32 before I started.
You need the oddly named MS media creation tool (links above). The only thing that worked for me was to run this and choose upgrade this PC now, in the guest. The rest is details - you can stop reading now.
On my experience, do not download the standalone ISO image. The ISO doesn't work, because, stupidly, it does not upgrade. It only installs. Running setup.exe in the guest off the ISO, my Win 7 licence key failed and that was it. Maybe there are some command line switches you can use to force an upgrade, but I didn't bother to look for them.
The first attempt failed with an old MS install error about failing to set up a working directory. I extended the guest partition by 10GB and this problem went away. I also ran the media creator as an admin, because on reflection it seemed nuts not to.
Telling the media creation tool to 'upgrade this PC' allows a cleanish ('keep nothing') install and activates without asking for a licence key. I didn't try any other kind of install. The display compatibility issue just gets ignored because of course it's not an issue. Once Win 10 is running, the guest additions install and work without problems using the VB Win 8 driver.
'Keep nothing' keeps your old Windows structures in /Windows.old. It zaps My Documents and Program Files, and leaves non-standard folders untouched. You will want to delete /Windows.old good and proper.
This is a 32 bit guest. Win 10 would not boot without PAE/NX, even with less than 3GB RAM. You only find this out about an hour in, when the Win 10 boot loader abends. The installer recovers, but throws away your image, giving you the opportunity to download a whole new one. The PAE/NX setting didn't stick at first, so I ended up learning this twice. I will never get those electrons back.
Guest is now Win 10 Home 32. Host is Win 8.1 Pro 64 running VB 5.0.0.
AMD, because it's not Intel.