I wanted to upgrade one of my Windows 7 laptops to Windows 8(.1) to run GOG Galaxy client, but that failed spectacularly.

Simple update

I thought I'd make a simple bootable USB and then just install the upgrade. That failed. Nothing worked anymore. Then I thought I might as well install clean, because there was nothing that important I wanted to keep. I also hoped I might have more success. Well that hope was in vain. I kept getting an error on the partition screen that it could not find a partition even though I just created one.

Well if you are ever stuck, hit Shift+F10 and in the Command Prompt type in type X:\Windows\panther\setupact.log. In my case it spat out that it could not determine a boot disk from the BIOS. So I changed the boot order in the BIOS. That did not help anything.

Then I had a small idea, what if I create a bootable partition on the main disk and copy the setup files there and then boot it.

A crazy idea

So here goes:

> diskpart
diskpart> list disk       # Check how much space the USB is taking up
diskpart> select disk 0   # Choose the disk you want to install to
diskpart> clean           # will delete everything, hope you have backups!
diskpart> create partition primary size=<SIZE> # Replace <SIZE> with HDD - USB in MB
diskpart> create partition primary size=<SIZE> # USB in MB
diskpart> format fs=ntfs quick
diskpart> assign          # assigns a drive letter, became E: for me
diskpart> active          # makes the install partition bootable
diskpart> list volumes    # to see what drive letter got assigned
diskpart> exit

Then run xcopy C: E: /E /H which means copy all files from C:\ to E:\ our newly created temporary partition. The flags /E /H mean copy all empty and non-empty files recursively including system files as well.

After that reboot with USB removed. Then you are able to continue.