Feb 14, 2009
I was having problems transferring files from one external USB drive to another. They were both attached via a powered USB hub. I tried running TechTool Pro on the drive I suspected with having a problem but it kept hanging.
The system.log showed this whenever it happened:
AppleUSBEHCI[0x6dfc000]::Found a transaction past the completion deadline on bus 0xfa, timing out!
I finally switched cables and removed it from the hub and plugged it directly into the computer. Seems to work fine now…but I should check it with the old cable again…