Perhaps I've just not figured the way around it yet.
I archive certain e-mails before I delete them. I had 300 M left on a disk and it told me that there was just no room, I couldn't move more stuff.
So I assembled a new disk, carefully checking the space. High 500's -- time to write out.
It asked if I wanted to write a "live file system" (which would be like a dongle) or a "mastered" disk. The difference they described was that I could easily delete file from the live thingy, whereas the mastered would work in most computers. Both of those make me think I want the "mastered", but I read up on more differences.
Ah. The "mastered" needs to be all assembled at once. So that would then be a "single session" disk -- and that could be why my prior one failed to allow me to add files.
So, with over 9,000 files, I said "write 'em", and instead of "mastered" I chose the live file system. It said ok, it laid down some formatting, and then all the files I had to write out no longer appeared on the "D" drive. YIPES.
Thankfully, I have a link to the "burn" location, and I've dragged those files back to the CD, and hope to "write" them soon.
But what I want is a multi-session disk which will contain a small (4 of 5) number of sessions, from which I cannot delete files. Feh.