How is the HD connected - USB or Firewire?
USB and FireWire Quick Assist
What to do if your computer won't recognize a FireWire device
Dealing with FireWire problems (drives not mounting, devices unrecognized, etc.)
Common fixes for USB device issues (unrecognized, etc.)
I trust you are very knowledgable and can help me. I have never had any problem accessing my files in my external hard drive. For some odd reason I can't access them anymore. The only different thin I can think of is updating my Mac to OS.
Below is a screen-shot of what comes up.
I would REALLY appriciate your help/advice.
Thank you kindly,