Using the current kernel, 2.6.9-5.0.5.EL, my Thinkpad 600E locks up hard when transitioning from battery to AC power. When this happens my only recourse is to power-cycle the machine. There is no indication in the system log of this event when the machine comes back up. Today I caught the event in the act. While the machine was booting, the AC power failed (bad storm here). The machine continued the boot process on battery power for several seconds. Then the AC power was restored and the machine locked up in mid-action. The apmd driver had not yet loaded yet so it can't be blamed for the lock-up. Previous to installing CentOS4 I had RHL v9 on this machine. In that environment the cycling of power from AC to battery back to AC caused only a few notes in the system log. Can anyone shed some light on how I can avoid the machine locking up on AC power restoration? Thanks.