5 Replies Latest reply: Apr 15, 2012 10:05 AM by BDAqua
botonzico Level 1 Level 1 (0 points)

I've gone for hours through all kinds of forums without finding a proper answer, so here I am.

This morning I've installed OS Snow Leopard 10.6.3 on my iMac, previously I had OS Tiger 10.4.11 running. Everything seemed fine until I restarted and then I started getting "USB drawing too much power" promps all over the place even though the only thing that's attached to the iMac is the keyboard and the mouse (they both work fine). The process went like this:

  • The iMac is a 2.4 GHz Intel Core Duo from october 2007
  • First I did an upgrade of my RAM, from 1GB to 2GB, that went ok.
  • Then I runned the install dvd for Snow Leopard, I did not perform a clean install, just did it over my old data. After restart, everything worked but i got this USB warning message, one of them. At that point my usb's still worked, (even though the warning) I could print and scan. To get rid of the warning, i resetted the PRAM and SMC, as suggested everywhere. After doing so, the promps multiplied and my usb ports ceased working, except for the keyboard and the mouse attached to it.
  • I've done the Apple Hardware Test, and it gives no malfunctions.
  • Firewire works fine, Isight buildt-in camera and bluetooth too.
  • I've tried all usb's and the keyboard will work in all of them, not like my printer and scanner which are completely ignored.
  • USB power warning also appears at restart with no deviced connected (no keyboard and mouse, i've tried).
  • I've also found in many forum entries  the possibility of a problem on the logic board, but since i've never had a problem with my imac until today i would not be sure about a hardware malfunction.
  • The last thing i've found around that could be a clue is something about the kernel extensions, but that's complete chinese for me, I'm  a mac plug&play user and not too much of a mac expert.

Does anybody have an idea about what could be going on? Should I perform a clean install of snow leopard? Would that solve the problem?

Many thanks in advance to the community for the help, I'm quite lost since I've owned macs for the last 15 years and this is the first problem I have with one.


iMac, Mac OS X (10.4.11)