[X4U] Mac locks up when attempting use file sharing

[Michael Elliott]

I know that this sounds like a completely bizarre suggestion, but  
have you tried disconnecting any connected USB or Firewire cables  
from your computer?

I had similar unexplained lockups and slowdowns during file  
transfers, and if memory serves, found some bizarre combination of  
USB hubs/peripherals was causing the problem.

I can get a complete freeze of the UI on my system; can't force-quit,  
invoke terminal, etc.  But I can simply yank the USB cable out of my  
iMac (thereby disconnecting a couple of hubs, multiple external  
drives, scanner, etc...yes I know not advisable) and suddenly my  
system will spring back to life.

Let me know if that helps.

Michael