I succeeded in writing data into an empty BD-RE .
But,I've not succeeded in rewriting BD-RE after erasing .

OS is debian 7.6,
and BD drive is Buffalo BR-X816U2.

First,
"Tools" → "Format/Erase rewritable disk" failed.
I checked only "Quick format", not "Force".
The reason of not checking "Force" is that I've seen somewhere
$ dvd+rw-format -force /dev/sr0
is not recommended for BD-RE.

It's Debugging Output is log1.

Second,
Since I heared K3b automtically erase rewritable media before rewriting,
I tried rewriting from "New Data Project",
but the following message appeared.
"Could not determine size of resulting image file."

It's Debugging Output is log2.

Would anybody help me?
Thanks in advance.


--------------------log1---------------------------
Devices
-----------------------
PLDS DVD+-RW DS-8A5SH XD12 (/dev/sr0, CD-R, CD-RW, CD-ROM, DVD-ROM, DVD-R, DVD-RW, DVD-R DL, DVD+R, DVD+RW, DVD+R DL) [DVD-ROM, DVD-R Sequential, DVD-R Dual Layer Sequential, DVD-RAM, DVD-RW Restricted Overwrite, DVD-RW Sequential, DVD+RW, DVD+R, DVD+R Dual Layer, CD-ROM, CD-R, CD-RW] [SAO, TAO, RAW, SAO/R96P, SAO/R96R, RAW/R16, RAW/R96P, RAW/R96R, Restricted Overwrite] [%7]
HL-DT-ST BD-RE BH10NS30 EL00 (/dev/sr1, CD-R, CD-RW, CD-ROM, DVD-ROM, DVD-R, DVD-RW, DVD-R DL, BD-ROM, BD-R, BD-RE, DVD+R, DVD+RW, DVD+R DL) [DVD-ROM, DVD-R Sequential, DVD-R Dual Layer Sequential, DVD-R Dual Layer Jump, DVD-RAM, DVD-RW Restricted Overwrite, DVD-RW Sequential, DVD+RW, DVD+R, DVD+R Dual Layer, CD-ROM, CD-R, CD-RW, BD-ROM, BD-R Sequential (SRM), BD-R Random (RRM), BD-RE] [SAO, TAO, RAW, SAO/R96P, SAO/R96R, RAW/R16, RAW/R96P, RAW/R96R, Restricted Overwrite, Layer Jump, Random Recording, Sequential Recording, Sequential Recording + POW] [%7]

System
-----------------------
K3b Version: 2.0.2
KDE Version: 4.8.4 (4.8.4)
QT Version: 4.8.2
Kernel: 3.2.0-4-amd64


--------------------log2---------------------------
Devices
-----------------------
PLDS DVD+-RW DS-8A5SH XD12 (/dev/sr0, CD-R, CD-RW, CD-ROM, DVD-ROM, DVD-R, DVD-RW, DVD-R DL, DVD+R, DVD+RW, DVD+R DL) [DVD-ROM, DVD-R Sequential, DVD-R Dual Layer Sequential, DVD-RAM, DVD-RW Restricted Overwrite, DVD-RW Sequential, DVD+RW, DVD+R, DVD+R Dual Layer, CD-ROM, CD-R, CD-RW] [SAO, TAO, RAW, SAO/R96P, SAO/R96R, RAW/R16, RAW/R96P, RAW/R96R, Restricted Overwrite] [%7]
HL-DT-ST BD-RE BH10NS30 EL00 (/dev/sr1, CD-R, CD-RW, CD-ROM, DVD-ROM, DVD-R, DVD-RW, DVD-R DL, BD-ROM, BD-R, BD-RE, DVD+R, DVD+RW, DVD+R DL) [DVD-ROM, DVD-R Sequential, DVD-R Dual Layer Sequential, DVD-R Dual Layer Jump, DVD-RAM, DVD-RW Restricted Overwrite, DVD-RW Sequential, DVD+RW, DVD+R, DVD+R Dual Layer, CD-ROM, CD-R, CD-RW, BD-ROM, BD-R Sequential (SRM), BD-R Random (RRM), BD-RE] [SAO, TAO, RAW, SAO/R96P, SAO/R96R, RAW/R16, RAW/R96P, RAW/R96R, Restricted Overwrite, Layer Jump, Random Recording, Sequential Recording, Sequential Recording + POW] [%7]

K3b::IsoImager
-----------------------
mkisofs print size result: 0 (0 bytes)

System
-----------------------
K3b Version: 2.0.2
KDE Version: 4.8.4 (4.8.4)
QT Version: 4.8.2
Kernel: 3.2.0-4-amd64

Used versions
-----------------------
mkisofs: 1.1.11

mkisofs
-----------------------
/usr/bin/genisoimage: Volume ID string too long

mkisofs calculate size command:
-----------------------
/usr/bin/genisoimage -cdrecord-params 0,677 -prev-session /dev/sr1 -gui -graft-points -print-size -quiet -volid RealProgrammer -volset -appid K3B THE CD KREATOR (C) 1998-2010 SEBASTIAN TRUEG AND MICHAL MALEK -publisher -preparer -sysid LINUX -volset-size 1 -volset-seqno 1 -sort /tmp/kde-owner/k3bVr5837.tmp -rational-rock -hide-list /tmp/kde-owner/k3bWl5837.tmp -joliet -joliet-long -hide-joliet-list /tmp/kde-owner/k3bxL5837.tmp -no-cache-inodes -full-iso9660-filenames -iso-level 3 -path-list /tmp/kde-owner/k3bxv5837.tmp

For the second burn - it seems the "Volume Name" is too long - could you try shortening the name you tried to set for the disc?

It didn't work. So I've given up.
Very sorry for forgetting to reply.