Migrating Libraries to 5.2

I am trying to migrate a library from Capella 1.4.2 to 5.2. I run into some issues. I get the following result:

The same process has worked for other libraries and I am trying to figure out what goes wrong here.
Do you have an idea of what could be going wrong?


My first guess would be that the aird has lost its reference to the .capella file.
The file has been renamed from .melodymodeller to .capella at some point.

In your library, you shall have a .aird and a .capella file after migration.
And if you open the .aird file as text, in the top you shall have reference towards the .capella file that is located aside.