Hi Andre,
I'm afraid somehow you did an overwrite on your Manager with the update installer. However, let's try to save what you have now:
1. Check if your previous Manager is still existing. Check if the installation folder is available and has files. If yes, we can try to fix this Manager if you contact me in PM.
2. If you can't find, then installing a new BIMcloud is a good track. In this case it is enough to have a new Manager, and following this article, you can pair your existing Server:
https://helpcenter.graphisoft.com/knowledgebase/86871/ However, you will lose your users and roles created prior.
Kind regards,
Noémi Balogh
Senior Community Expert, Admin