I just had Core installed on my HP DL320e Gen8 server via (2) m.2 USB drives. Decided to wipe everything and install Scale.
Made another boot device with scale on it, selected my (2) m.2 devices to install on, tried both UEFI and/or BIOS [Yes/No] after I fully wiped them and get this error either way, it seems like it sees the drives one second, then it can’t find them?
I flashed and re-flashed several times with Rufus/Etcher and nothing has worked, this error is persistent.
Found an older post but unclear of what this guy did to fix it:
There’s an acknowledged bug in the installer but, due to a complete re-write for forthcoming Electric Eel, there’s believed to be little value in fixing this one. (I submitted this bug and the explanation from iX is along those lines, which I think is fair enough).
The solution which I found to work was to say “yes” to EFI boot and, even though my Gen8 does not EFI boot, the machine starts fine and always has done.
You’ll see the screenshots I submitted in the thread I showed you; I think they do look similar to yours, but what do you think?
I reckon that your best bet, based on my experience of spending hours and days and weeks trying to solve things, is to simply reinstall as per the comments in my posts and that should/might/will be that!
I’ve already sent the link in my original response above; click on that link and scroll down to see the screenshots.
When you worked through the installation process yourself, you have already seen the bit where it asks you if you want to choose EFI or legacy - you showed a screenshot of it:
Choose EFI by saying “yes” instead of “no” and see how you get on. It has worked for me and I have been trying to repair something unrelated so I have reinstalled several times this week. it takes about 10 minutes, including waiting for the machine to boot.