|If you got the message while booting the computer, your mboard/cmos battery is too weak, dead, installed backwards, not installed, or has a poor connection.|
You have to set at least the date and time, either in the bios Setup, or in your operating system, in that case, and fix the problem or replace the battery. The time and date are retained when you reboot, but are lost again when the computer is shut off, and you will get the message again when you boot after that.
USB devices may not work correctly when they're connected to certain USB ports, e.g. ports in a hub or on the front of a desktop case.
See response 3 in this:
External drives require a lot of power, and they won't work properly in all possible USB ports you can plug them into.
See response 1 in this:
If the circuits in the external case are being detected correctly, there is a listing for a mass storage device under USB Controllers in Device Manager for that (Control Panel - Device Manager). If there is more than one of those, USB flash drives and memory card readers also have that entry there. If you RIGHT click on the USB Root Hub entries there, then Properties - Power - the USB devices connected to that hub, if any, are listed, and the amount of current they use is specified. External drives, when connected to one USB port, draw 500ma or not much less than that, if they're getting enough power from the port they're plugged into - everything else draws less current.
If the hard drive inside the external enclosure is being detected correctly, it's model shows up in Control Panel -Device Manager - Disk Drives,
and in Disk Management (Control Panel - Administrative Tools - Computer Management - Disk Management), even if there's something wrong with the data on the hard drive or the drive is blank of data,
and in My Computer and Windows Explorer if there's nothing wrong or not much wrong with the data on the drive and the drive has been software partitioned and formatted using something the operating system recognizes (NTFS, FAT32, or FAT).
A thing people frequently forget to do (or are not aware of) is that when you want to unplug an external drive (or a flash drive, or a memory card reader that plugs in) while the operating system is running, you are supposed to click on the Safely Remove Hardware icon in your taskbar lower right, and STOP accessing the drive you want to unplug. In Vista it's a mid green circle with a thick white checkmark on it - it may be hidden - you may need to click on the < at the left end of the icons in the taskbar to reveal it. If you were accessing the drive at the time you click on the Safely Remove icon, you may not be allowed to STOP accessing the drive - in that case, access some other drive, then click on the Safely Remove icon.
If you haven't been doing that every time you unplug the drive, the data on the drive is usually not damaged, but sometimes it IS damaged, and in that case you need to use a program to repair the damage.
e.g. these suggested by aegis1 in a previous post...
No harm in trying a file recovery program. Depending on the amount of corruption, they can recover data with both FATs bad.
PC Inspector (freeware)
Zero assumption Recovery
The demo is limited
It will only recover 'up to' four folders per run
But you can make multiple runs
Really good, but you have to pay for it.
From my own experience,. I found that if you want to test the hard drive inside the external enclosure with diagnostics, you have to remove the hard drive from the enclosure and connect it internally to a desktop computer.
If the drive is 3.5" (desktop sized) that's fairly easy.
If the drive is 2.5" (laptop sized),
- if it's IDE, you can buy an inexpensive laptop 2.5" IDE to desktop 3.5" IDE adapter and connect to an IDE data cable.
- if it's a SATA drive, I'm not sure how you would connect it to a desktop computer, if the SATA data cable connector socket for the 2.5" drive is different from than that used for a desktop SATA drive data cable end connector - perhaps someone else who answers here knows??
Check your hard drive with the manufacturer's diagnostics.
See the latter part of response 1 in this:
(thanks to Dan Penny for this link:)
Hard Drive Diagnostics Tools and Utilities
If you don't have a floppy drive, you can get a CD image diagnostic utility from most hard drive manufacturer's web sites, but obviously you would need to make a burned CD, preferably a CD-R for best compatibilty, on another computer if you need to.
If the hard drive itself tests okay, any data problems found can be fixed, one way or another.