| Cause | Explanation | |-------|-------------| | | A feature or cumulative update may have overwritten the correct driver with a generic Microsoft one. | | BIOS Update | A BIOS update can change ACPI tables, making the old driver incompatible. | | Driver Cleaner tools | CCleaner or Driver Booster may have "optimized" away a needed system driver. | | Corrupt system files | sfc /scannow may reveal corruption in the ACPI stack. | | Manual driver uninstall | Uninstalling "unknown device" accidentally removed the function key driver. | | Hardware conflict (rare) | Another power management device is using the same IRQ. |
If you still have access to your Windows installation and have an internet connection: acpi fnbt0000 driver fix
Toshiba has rebranded its support site (now often redirecting to Dynabook). You need the . | Cause | Explanation | |-------|-------------| | |
Before diving into fixes, ensure the issue is indeed related to this driver. Look for these telltale signs: | | Corrupt system files | sfc /scannow