Thanks again for your replies Romantique Tp. I have carried out all of your purposed actions but unfortunately the problem remains. But at least we´re getting closer to the core of this issue. It´s exactly those four sound libraries that´s in the “Managed” tab of the Library Manager that´s not working. All libraries under the “Installed” tab runs just fine.
Judging by your last sentence it seems like this is not the first Missing Content Issue. I hope Steinberg is working on a sollution.
I will try to make a call to the Steinberg support tomorrrow.