Warning: os-prober will not be executed to detect other bootable partitions

Sabine · August 30, 2026, 5:55am

What should I do if I see this error message?

Warning: os-prober will not be executed to detect other bootable partitions.
Systems on them will not be added to the GRUB boot configuration.
Check GRUB_DISABLE_OS_PROBER documentation entry.
Adding boot menu entry for UEFI Firmware Settings …
done
Reading package lists…
Building dependency tree…
Reading state information…

disp7321 · August 30, 2026, 9:52am

It’s not an error, but a warning that tells you that os-prober won’t be executed.

This is the reason for this:

github.com/QubesOS/qubes-secpack

QSBs/qsb-020-2015.txt

main



             ---===[ Qubes Security Bulletin #20 ]===---

                            July 27, 2015


                 Fedora os-prober considered harmful


Quick Summary
==============

Rusty Bird, while testing our patch for the AEM attack that was the
subject of the previous bulletin (QSB #19), noticed that the
os-prober, a standard Fedora package used for dual-boot configuration
discovery and maintenance, is processing some of the internal Qubes
block devices, used by the Xen backend. This might allow an attacker,
who compromised one of the VMs, to prepare a malicious content on the
VM's private image, which, upon processing by the Fedora os-prober

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Sabine · August 30, 2026, 10:17am

Thanks. I thought that restarting the laptop might cause it to completely shut down.