I have a new iMac, and recently purchased some DVD+RW and managed to burn some video files to it with no problems.

I now want to add some more video files, the disc is not full, but I can't seem to get it to work.

The DVD icon shows on the desktop and when i try and drag and drop the file onto it it gives me the message that the file cannot be moved their because "the disc cannot be modified".

I've never used re-writable discs before, so is there something I'm missing that I have to do?

I've searched the forum but with no luck, i hope someone can help.

Many thanks in advance guys