Hi zoozoo,

I don't know that we have enough information to give you a solid answer. We need some context such as the permissions of the file/dir in question. Are both clients attempting to hit the same export/dir/file? What is the error being return?

You may want to considering opening a service request with Isilon Support so that they can help gather the necessary details.
https://onlinesupport.emc.com/SRCreate

Hi sjones5

Thanks for your answer.

yes, both clients attempted to hit the same export dir/file.. but detail file permission were not collected... sorry

If the problem recur  I'll ask you again.

Thanks