K3B doesn't recognise disc in drive

It seem i have 2 problems.

If the iso image is too large, K3B does not say so. It acts as if it did not see the blank DVD.
I am not sure but some tests might have been done with images for double layer.
This could explain some of my failed tests. I tried so much options that i am not sure if
there is not something else too. I can now burn DVD’s though, the main objective.

With the internal LG drive (GH22LP20) and K3b i cannot erase or write on CD-RW. WIth the external
USB DVD Drive (TSSTcorp) i can write the CD but the behavior is strange. It start by trying to erase
the CD-RW, report a failure but proceed with writing the iso image normally. I am not sure the internal
drive is defective of if it is K3B that cannot handle it well.

Thanks a lot for the suggestions.

Sylvain

I never work from the notification popup in kde
I work directly with k3b, so I start it up.
Insert a optical media (usually I work with blank media) to burn a SUSE .iso
With the blank DVD in, I use the k3b file browser to navigate to the .ios and click on it. k3b loads the .iso and starts a md5sum check, once that is done I run the burn.

Making a data DVD, I start k3b, with blank media added I do: create a Data Project. As I add individual files and or folders it incrementally shows the remaining space very accurately.

I have had trouble blanking, but the results are not consistent to give any opinion.