Is the external HD enclosure have its own power or does it draw power from the USB connection? If it's drawing power from the USB port on the laptop it's possible that when your system probes the busses for connected devices the hard drive either hasn't gotten power yet or it has gotten power but there may be on-board diagnostics on the external hard drive enclosure that are still going on. This would result in the device not being detected. It sounds like this may be your issue. A couple ways to check this:Originally Posted by minghi
1. once laptop is on but external HD is not detected, open the My Computer icon and hit F5. This forces a refresh (may not work with USB drives, not at home at the moment to check for sure) of drives. or;
2. Disconnect and reconnect the drive into the USB port on the laptop after your inital boot when the drive is not being seen. If the drive pops up then it would indicate what I mentioned.
About rebooting the laptop and magically the drive appears the second time: a reboot does not cycle the power (it's a 'soft' reset) so when the bus probe occurs for connected devices the second time around the drive has power and responds to the probe and Windows sees it.
If this really bugs you you can possibly fix it by doing the following: Boot the laptop up and get the external drive connected and functional in Windows. Then, modify your boot.ini file in C:\ to add /FASTDETECT. i.e.
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Micro soft Windows XP Home Edition" /fastdetect
Then shutdown and restart.
Specifying FASTDETECT causes NTDETECT to skip parallel and serial device enumeration for a boot into Windows which (IIRC) will cause Windows to use the previously saved shutdown configuration in regards to connected devices so they will show up (even if not connected).