External HD claims to be drawing too much power, after 2 months of working

Question

I have a 2.5" external HD enclosure from Mad Dog Multimedia that uses two USB connections, one for data and one for power. It's been working fine with my new Macbook Pro since I bought it several months ago, and continues to work fine with other comptuers. Last night I got a message that it was drawing too much power and the ports would be shut off. I unplugged and replugged it, and it continued to work all evening. This morning however, no matter what I do, it continues to tell me that its drawing too much power. This is baffling to me, because it has worked for the last few months, and still works on other computers, leading me to believe that something is wrong with my USB ports. Unfortunately I don't have much in the way of other USB devices I can use to test this hypothesis. Has anyone else encountered similar problems, and have you been able to resolve them successfully?

Answer 1

In the event you haven't done this already, shut down the computer and remove the external drive. Wait at least one or two minutes. Restart the computer then reconnect the external drive. See if your problem is resolved.
Try repairing the hard drive and permissions:
Repairing the Hard Drive and Permissions
Boot from your OS X Installer disc. After the installer loads select your language and click on the Continue button. When the menu bar appears select Disk Utility from the Installer menu (Utilities menu for Tiger and Leopard.) After DU loads select your hard drive entry (mfgr.'s ID and drive size) from the the left side list. In the DU status area you will see an entry for the S.M.A.R.T. status of the hard drive. If it does not say "Verified" then the hard drive is failing or failed. (SMART status is not reported on external Firewire or USB drives.) If the drive is "Verified" then select your OS X volume from the list on the left (sub-entry below the drive entry,) click on the First Aid tab, then click on the Repair Disk button. If DU reports any errors that have been fixed, then re-run Repair Disk until no errors are reported. If no errors are reported click on the Repair Permissions button. Wait until the operation complete. I also suggest you run Repair Disk on the external drive as well while you still have DU running. Now quit DU and return to the installer. Restart normally.
If DU reports errors it cannot fix, then you will need Disk Warrior (4.0 for Tiger, and 4.1 for Leopard) and/or TechTool Pro (4.6.1 for Leopard) to repair the drive. If you don't have either of them or if neither of them can fix the drive, then you will need to reformat the drive and reinstall OS X.
If the above does not work, it is possible there's a problem with your OS X installation. It's difficult to know what that may be so you will need to experiment. First, restart the computer in safe mode. If this doesn't result in the problem ceasing, then try creating a new user account. Log out of your account and log into the new one. If this doesn't result in the problem going away, then more extreme measures are needed: reinstalling OS X. You might give this a try:
How to Perform an Archive and Install
An Archive and Install will NOT erase your hard drive, but you must have sufficient free space for a second OS X installation which could be from 3-9 GBs depending upon the version of OS X and selected installation options. The free space requirement is over and above normal free space requirements which should be at least 6-10 GBs. Read all the linked references carefully before proceeding.
1. Be sure to use Disk Utility first to repair the disk before performing the Archive and Install.
Repairing the Hard Drive and Permissions
Boot from your OS X Installer disc. After the installer loads select your language and click on the Continue button. When the menu bar appears select Disk Utility from the Installer menu (Utilities menu for Tiger.) After DU loads select your hard drive entry (mfgr.'s ID and drive size) from the the left side list. In the DU status area you will see an entry for the S.M.A.R.T. status of the hard drive. If it does not say "Verified" then the hard drive is failing or failed. (SMART status is not reported on external Firewire or USB drives.) If the drive is "Verified" then select your OS X volume from the list on the left (sub-entry below the drive entry,) click on the First Aid tab, then click on the Repair Disk button. If DU reports any errors that have been fixed, then re-run Repair Disk until no errors are reported. If no errors are reported, then quit DU and return to the installer.
2. Do not proceed with an Archive and Install if DU reports errors it cannot fix. In that case use Disk Warrior and/or TechTool Pro to repair the hard drive. If neither can repair the drive, then you will have to erase the drive and reinstall from scratch.
3. Boot from your OS X Installer disc. After the installer loads select your language and click on the Continue button. When you reach the screen to select a destination drive click once on the destination drive then click on the Option button. Select the Archive and Install option. You have an option to preserve users and network preferences. Only select this option if you are sure you have no corrupted files in your user accounts. Otherwise leave this option unchecked. Click on the OK button and continue with the OS X Installation.
4. Upon completion of the Archive and Install you will have a Previous System Folder in the root directory. You should retain the PSF until you are sure you do not need to manually transfer any items from the PSF to your newly installed system.
5. After moving any items you want to keep from the PSF you should delete it. You can back it up if you prefer, but you must delete it from the hard drive.
6. You can now download a Combo Updater directly from Apple's download site to update your new system to the desired version as well as install any security or other updates. You can also do this using Software Update.