I have a computer that has suddenly started refusing to boot Unraid. An Ubuntu install image flashed onto a new USB stick works, but the Unraid installer (7.2.3 or 7.1.4) won't boot. The computer detects the USB stick, and I can prompt it to try UEFI or legacy booting the stick, but it just kicks me back to the bios with no indication why it's failing.

I'm reluctant to tamper with the original USB stick, but I've tried two new sticks, a 128GB and a 16GB, with various combinations of things:

• Using Rufus to format the 128GB as Fat32 before manually coping the Unraid files

• Starting with flashing the Ubuntu image and then deleting the files and copying Unraid on.

• Copying those Unraid files from a fresh 7.1.4 install zip, 7.2.3 install zip, as well as from the old USB stick.

• Copying the "previous" directory from the old USB stick over the root to "downgrade" from 7.2.3 to 7.1.4

I've also tried a bunch of BIOS options. "Fast boot" has been off since long before this. I've tried disabling the CSM. Nothing has helped.

The motherboard is a Asus Z87-PRO, for whatever that's worth.

I'm at a loss.

I've got TB of data on this server, so I'm a bit panicked about not being able to get Unraid to boot at all. It was running fine on 7.1.4 until I hit upgrade, and then it wouldn't boot.

Edited January 15Jan 15 by SurprisingEdge

I found help elsewhere and figured this out.

My BIOS has two options for SecureBoot: Microsoft and Other OS.

It's been set to Microsoft forever. Always worked fine. For some reason, it stopped working fine. Changing it to Other OS fixed things. Unraid boots fine now.

Notably, the official troubleshooting doc for boot issues doesn't once mention Secure Boot. 😒