I bought two Western Digital 500GB MyBook Pro drives and hooked it to my mac pro via the firewire outputs. All worked well for the first two weeks. Now, the drives don't show up anymore. From some reading I have done across the Internet I suspect the problem might be during the last OS X software update. Seems if you don't disconnect the drives (even if OFF) during an update they somehow will be removed. Can anyone confirm this is the issue and at the same time tell me how to get the drives working again so they appear on my desktop? Thanks in advance!