What happens when you try to format/erase the disk with K3b?
You have not described the problem .......
It shows as a blank disc but it has 3 folders from its first burn.
Also, with another CD-RW, on trying to add files and when I click on Burn, K3b pops up a box asking "should it be erased" or "eject".
OK, that is what it shows, but you have not said what happens when you select to erase/format it!
Too late to tell you because I can't remember, it just wouldn't erase/format and I can't repeat the operation because I have successfully erased the CD-RW in question with software from another distro. Thanks for your time.
As for my previous/additional query (#4) "should it be erased" or "eject" I'll post again if I can't figure out why K3b wants to erase before burning, on multisession.