I have Cubase Pro 13, I just had the same problem with the Windows 10 update although before everything worked perfectly, I know that Steinberg works closely with Microsoft but no feedback? I tried everything and still the same Media Bay error problem? What should I do? Has anyone been able to solve this problem?
Thx
Vincent
Hello and welcome to the forum
Seems there is a problem with the updating of the Steinberg Download Assistant when it tries to install the latest Steinberg Mediabay.
I suggest to install the Mediabay first
Make sure no Steinberg software is running during the installation.
Hi,
Thank you for your quickly response and the link.TOP!
I have just tried installing Mediabay, I no longer have the error message but obviously there is a problem with Groove agent SE?, yet it is there and works standalone. It’s a good start.
Why did the Windows update cause this malfunction? That’s the problem for me since everything was working before.
Thank you Fantom 
Sure,
You can install Groove Agent from here:
A propos …
This page gives a lot of info:
https://helpcenter.steinberg.de/hc/en-us
Hello,
I think the problem comes from the software. As I wanted to reinstall everything there are several Vst it does not update. Cubase works without problems.
I think I’ll ask Steinberg what’s going on.
Thank you very much Fantom for your help, it’s GREAT !
Run Steinberg Download Assistant as Administrator. In my case it solved the issue.
Hi, Thanks for your reply. The problem has been solved, I’ve installed a new SSD and reinstalled everything. There were quite a few files missing, hence the problem that the SDA couldn’t find certain files. This was caused by a Windows update. Merry Christmas 