Q: Mouse and Keyboard disconnecting??

Can someone please help - this is driving me insane....

My Mac is approx 2 years old and I have never had an issue. I updated last week to the new Yosemite software. Ever since, whenever my Mac goes to sleep, I can't use the keyboard or mouse to wake it up - In the end I have to reboot the whole system.

Does anyone have any idea what has happened?

All the bluetooth settings etc look fine.

Thanks!