I used the thinkvantage system update software to update my power manager and hotkey on screen display features, once upgraded/updated I can no longer control the brightness with the keyboard buttons or any other method. I cannot change power manager profiles either, the only way i resolved this was to reload my pc to its original factory settings thinking the problem was only with power manager. After reloading the pc i Didn't update power manager but updated the hotkey on screen display features with the system update from thinkvantage and now im almost back to square one, now I don't want to update my power manager. The only possible way I can get the brightness to go slightly lower is to activate battery stretch.
Is there a bug fix for this from lenovo because i've looked and i only see bug fixes for the power manager, however they are old and don't do anything for my system (and i actually liked the new power manager features)