I try to upgrade a OES2015SP1 to OES2018. When I come to choosing the
System-Partition (aka root) I get en error that the installer can not
mount partitions.

The partition in view are for /var. This, and the directory /tmp are on
separate partitions.

The order for the partition at the system disk are:

When check the mounted partitions in another console it seems that the
installer try to mount all partitions to /mnt. But the root-partition is
mounted there already ...

Any hints?


BTW: Devices were mounted via Device-Path.