Comment # 1 on bug 1046414 from Terje J. Hanssen

Addon:
I tested to install from this openSUSE-Leap-42.3-DVD-x86_64-Build0289-Media
(DVD+R) on another, second workstation and got the same issue.
Then I downloaded the iso again on this workstation and burned it on a DVD+RW
disc. Using this media I succeeded to run both Upgrade and New installation on
both workstations.

Possibly the issue could be caused by:

- Faulty first time downloaded iso
- Faults when burning on DVD+R media
- Faults with the first DVD writer device