Hyper-V: “fixing” the error “The signed image’s hash is not allowed (DB)” while booting a Linux ISO image
Posted by jpluimers on 2026/09/25
I got a “The signed image’s hash is not allowed (DB)” when booting an OpenSUSE Linux ISO Image:
[It was the signed image ftp.uni-kl.de/pub/linux/opensuse/distribution/leap/15.5/iso/openSUSE-Leap-15.5-DVD-x86_64-Build491.1-Media.iso which isn’t trusted by Hyper-V to perform UEFI secure boot.
Technically, the UEFI secure boot specifications support adding acceptable digital signatures in order to allow booting from media not signed by Microsoft, but alas, Hyper-V does not allow that option as per [Wayback/Archive] Secure boot with custom keys – Microsoft Q&A.
The not so satisfying solution is to turn off secure booting for this particular VM in Hyper-V from the VM-options (Ctrl-O) menu with the steps below.
Before following these steps ensure your VM is powered off.
- Under “Under Security”, you see the default “Secure Boot enabled” setting that we want to disable:
[Wayback/Archive] p.png (228×256) - Click “Security”, then uncheck the “Enable Secure Boot” setting:
[Wayback/Archive] p.png (666×107) - Click the “OK” or “Apply” buttons after disabling Secure Boot:
[Wayback/Archive] p.png (666×109) 
[Wayback/Archive] p.png (301×44)- Now Secure Boot is disabled:
[Wayback/Archive] p.png (228×253) - Boot your VM and all should be dandy now.
Query
[Wayback/Archive] “The signed image’s hash is not allowed (DB)” – Google Search found a related post with mixed screenshots in English and German at [Wayback/Archive] Hyper-V UEFI error message: The signed image’s hash is not allowed – eKiwi-Blog.de.
–jeroen
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