Please, let me add one last thing. I figured out that when I start the machine while my keyboard is switched off, turning it on at the greeter doesn't work. I have to remove the Unifying Receiver and plug it in again while the keyboard is on in order to be able to type.
This strange behaviour was introduced in Precise.
I hope you have enough information at this point. Please feel free to ask for anything else.
Please, let me add one last thing. I figured out that when I start the machine while my keyboard is switched off, turning it on at the greeter doesn't work. I have to remove the Unifying Receiver and plug it in again while the keyboard is on in order to be able to type.
This strange behaviour was introduced in Precise.
I hope you have enough information at this point. Please feel free to ask for anything else.