No irq handler for vector / Failed to start Load/Save Screen Backlight Brightness of backlight:acpi_video0

[stephane]

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Manjaro won't boot after update, Failed to start Load/Save #ness of backlight:acpi_video0

That is a systemd service that tries to save the level of backlight for your monitor when you shut down and restore it when you boot. To disable that as it doesn’t seem to work on your system anyway (It doesn’t on mine neither) just execute: sudo systemctl disable systemd-backlight@.service As taken from the old forum.