I'm sorry we disappointed you. I know it can be frustrating if things don't work and there are no helpful replies. Let me try to clear things up.
It does. Please note that it is not working in your VirtualBox installation. However, the release candidate of UCS 4.2 is running fine as a virtual machine on common Type-1 hypervisors such as Xen (AWS) and KVM (I'm counting KVM as Type-1 here) - there are automated product tests for this and I verified it myself. VirtualBox is a Type-2 hypervisor and while those are great for testing things, they are not the right choice to run virtual machines in production. So please understand, that support of production relevant features has a higher priority than support for such features that are meant for testing.
That being said, I tried to reproduce your issue with VirtualBox (5.1.18, Windows 10) today, but it's working just fine for me I had no freezes. More on that further down.
No Virtual machines in general are just fine. But there might be a specific problem with VirtualBox.
I don't understand why there should be an extra forum just for a new minor version, to be honest. Maybe you can write more on that? Always happy to learn.
There is the category for UCS and there are tags for the UCS version. For UCS 4.2 it's
ucs-4-2, but people need to use it. Tags are great for sorting and searching.
The bug tracker is https://forge.univention.org
Of course it's not. By now, we ask the participants to use english in the posting guidelines.
Please understand that a large part of the userbase is german speaking and since Univention is based in Germany, many people tend to use german. We do understand that this is exclusionary and we try to change this step by step.
It is I encourage you to try another hypervisor or review your VirtualBox settings.
Don't get me wrong, this might as well be an issue with your setup and should not make you disappointed by the whole product.
Please understand that this is a community-driven forum. Although Univention staff members participate, there is no guarantee that someone at Univention will personally assist you here in the forum (we do have Enterprise Support for that). But be assured, that all topics on help.univention.com are monitored by Univention and that actual bugs get added to the bug tracker.
That being said, I tried to reproduce your issue. I downloaded the UCS 4.2 RC ISO here:
Then I installed the latest VirtualBox (5.1.18) on Windows 10 (amd64) and configured a new virtual machine. I chose 'Debian (amd64)' as template. The only default setting I changed was the network settings - I changed that from NAT to Network Bridge. Then I powered up the VM and was able to install UCS 4.2 without problems:
After the installation finished, I was able to access the webinterface: