Let me say: This is an unsupported scenario

Today I decided to do an in place upgrade of my LAB Installation, which means to switch from Microsoft Server 2012 R2 to Server 2016 as operating System. Before I started that upgrade, I made sure to have a proper backup of the database and the cd.latest Folder, because this is a single box installation.
Then I mounted the Server 2016 ISO and started with the installation. The installation itself took quite a while, but it ran through without an error. When I saw that the virtual machine was ready to logon, I actually tried to use RDP, without success. I then logged on through the Hyper-V Console and checked the System Center Configuration Manager Console, and for my surprise, the console started up and had also no error.
I checked the Component status and recognized a lot of issues, which led me to check the IIS Service (World Wide Web Publishing Service; W3SVC). This Service was not started, the startup type was on “Disabled”.

I then set the startup Type to “Automatic” and tried to start the service manually, but without success. I could not start the service, because the depending service “Windows Process Activation Service” was on disabled as well, and therefore not started. When I had started the depending service, I was able to start IIS too.

After that I was checking the component monitor again and the “SMS_REST_PROVIDER” could not be started, or more detailed, ConfigMgr was unable to reinstall this component. The following error message was within the logs:
The program failed for the following reason: Failed to install the VC redistributable.
I tried several things, but I was not able to resolve this error, until I installed both versions (x64 and x86) of the vcredist within the cd.Latest Folder. Afterwards everything seemed to work fine: Clients received Software, WSUS could sync (I was required to finish the role setup), the reports were working.