A number of the Users I admin for have CRM 2011 and work off of up to date MAC's all experiencing a similar error where in they cannot download/export a list from the CRM and open it in their Excel. They click the Export to Excel button and simply nothing happens, no sign of activity. This used to be an error in certain browsers but now has grown to include all browsers (Firefox, FireFox Nightly, Safari, Chrome etc.) again only in MAC. I have seen that downgrading the Users to an older version of IOS has been a solution, but requires extensive re-imaging potentially resulting in loss of data which is not a feasible solution for my department.
Any advice or direction would be extremely helpful. If you require any more information or clarity please feel free to ask.