This behavior, which occurred with Mac OS 7.6 and 7.6.1 under certain screen dimming conditions, was corrected in Mac OS 8. Upgrading to Mac OS 8 will resolve the situation.
Here are several possible workarounds:
- Don't set the Screen Dimming control in the PowerBook control panel to "never dim".
- Set both Screen Dimming settings (Battery and Power Adapter)to "never dim".
- Press the Power button, then click Cancel in the confirmation dialog box.