I'm a absolute Newbie to the Mac. Today, I almost lost something I've spent days working on so I thought I'd try to avoid that happening again. I have a box of brand new CD-RW. I opened one, loaded it, dragged the folder to the CD icon on the desktop, then "burned". All seemed good. Went back to work at the end of which thought well I'll backup again. No can do! The CD tells me I cannot do this because the "CD >>name<< Cannot Be Modified". In all innocence perhaps, I thought one could write many times to a CD with RW on it. Anyway, I'd be very grateful for advice & my apologies if I'm asking a really dumb question. In case it helps, mine is a MacBook Air & I'm using the MBA Superdrive