After update, grub doesn't find windows install

[Olli]

GRUB_DISABLE_OS_PROBER flag appears to be ignored in /etc/default/grub

After updating to version 2.04-17 re-generating the grub config with the update-grub command ignores the fact that GRUB_DISABLE_OS_PROBER=true is set in /etc/default/grub. The partition structure is as below - even though GRUB_DISABLE_OS_PROBER is set to true os-prober is still invoked and Windows Boot Manager is added to the boot menu. This does not occur in 2.04-16. The os-prober version is 1.77-1 but this has not changed. The issue occurs on both 5.4 and 5.10 series kernels. In either case…