my iMac has recently developed an odd issue:
If the mouse, or keyboard, is powered off (power button, or because I pull the batteries), and then powered on again, the device will not connect to the machine again without the whole system being power cycled.
These are: * Magic Mouse * Apple Wireless keyboard
On a late 2009 i7 27" imac.
Running all the latest patches. 100% battery on both devices. No matter how many times I click the mouse, or press keys on the keyboard will it reconnect.
It had happened previously, but after a few minutes it would usually resolve itself. In the past 3 days, it's started happening even without the device being powered off -- specifically the mouse stops working, and a power cycle fixes it.
Note that plugging in another mouse/kb (microsoft ones), works fine and I can use that to shut down the machine.