I used cbp files from cubasis3 using cubase 10.5 until last year and import worked fine, but after upgrading to cubase 12, I am unable to import cbp files.
When imported, it is unresponsive without generating an error. I reinstalled 10.5 to try, but could not import as well. The files are all alphanumeric characters and I have tried reinstalling cubasis project importer 3.0 but no improvement.
Can you please check the following tutorial chapter of our friend Jamie Mallender, which explains the steps to import the project into Cubasis:
Did you also select a new folder where to store the imported project to?
If the problem persists, it would be of great help if you could share the project with us, to allow us reproducing the problem. To do so, please upload the project via Dropbox or similar and let me have the download link via private message.