Thank you for your reply Geoff.
I should have mentioned, I ran all permissions with the "Apply to Enclosed Items" checked, having had learned that little gem previously. I have also deleted Lightroom preferences to no avail.
I have run disc utility on the external hard drive to repair permissions and nothing changed/improved.
However, I have not run disc utility on the mac pro hard drive. Do I run any risk and if so, can you suggest any tips?
It sure seems like a permissions issue but I have not been able to solve it yet.
Thank you in advance,
Jon