USB ports not working on 1st startup, okay on 2nd

[playthestatic]

I'm not sure if there's already a thread on this, please excuse me if there is.

Most times my iMac 7.1 starts up fine, but once startup is completed, I find that my USB ports don't appear to be working (USB mouse doesn't move, keyboard isn't responsive, any USB flash drives are not detected). I restart using the power button and on the second startup, everything is fine.

Can anyone tell me any way I can solve this problem? Is there reason for worry?

 

[BlueRevolution]

Hmm, there's definitely reason for puzzlement. 7,1... is that still under warranty? Only if you've bought AppleCare, I guess. We'll do some troubleshooting, but it'd be nice to know that if it turns out to be a hardware issue, there's somebody to turn to.

So, this is always an issue, every time you start up your computer? It's not an intermittent problem?

 

[hughvane]

Instead of a reboot, does unplugging the USB device and then replugging restore operations? I note that from time to time my USB keyboard ceases working, and the above technique restores functionality.
Next: have you a powered (not bus-pwrd) USB2 hub to try?
Last: do you eject volume devices like the flash drives before shutting down the iMac?

 

[playthestatic]

Hmm, there's definitely reason for puzzlement. 7,1... is that still under warranty? Only if you've bought AppleCare, I guess. We'll do some troubleshooting, but it'd be nice to know that if it turns out to be a hardware issue, there's somebody to turn to.

So, this is always an issue, every time you start up your computer? It's not an intermittent problem?

I'm quite sure it's no longer under warranty, which is a pity.

It doesn't happen all the time, but it does happen a lot - around 9 out of every 10 times I start it up. Sometimes it even freezes up at the grey screen with the Apple logo, and sometimes it gets to my desktop screen fine, but when I try to move my mouse, everything freezes. Then everything's suddenly fine when I restart with the power button.

Instead of a reboot, does unplugging the USB device and then replugging restore operations? I note that from time to time my USB keyboard ceases working, and the above technique restores functionality.
Next: have you a powered (not bus-pwrd) USB2 hub to try?
Last: do you eject volume devices like the flash drives before shutting down the iMac?

No, the unplugging and replugging doesn't work, strangely. I'm not entirely sure what a powered USB2 hub is (excuse the technology retard!), but I'm pretty sure I don't have one, all I've got are the inbuilt USB ports in my Mac and the ones on my Mac keyboard.

Yes, I do eject all the volume devices - but how would it cause problems, if I didn't? Just wondering.

 

[Powerbooky]

I have something similar with my Mac Pro. Sometimes the USB-keyboard and USB-mouse don't work at startup (or 2nd startup). The only sollution sofar is disconnecting the keyboard (alu-keyboard) and connect a different one (white Apple keyboard). That keyboard then is recognized and works. Reconnecting the alu-keyboard again and everything works as if nothing was wrong.
Strange.