MacBook, iMac: Maximum display brightness when connecting or disconnecting an external display
Symptoms
iMac and MacBook LCD panel brightness may brighten up to the maximum level when you connect or disconnect an external display.
Products Affected
MacBook (13-inch), MacBook (13-inch Mid 2007), MacBook (13-inch Late 2006), iMac (Mid 2006 17-inch), iMac (17-inch, Late 2006 CD), iMac (17-inch, Late 2006)
Resolution
Adjust the display brightness - on Apple portable computers, adjust the display brightness using the F1 and F2 keys at the top left of the keyboard. On iMacs with an Apple keyboard, adjust the display brightness using the F14 and F15 keys at the top right of the keyboard.