Cubase 9 doesn’t recognise audio from old projects

Has anyone experienced this issue: I have a project created in SX that opens fine in 7.5 but cubase 9 does not recognise the audio files as valid?
None of the audio has file extensions and if I add them cubase only recocognizes some of them.
All the audio files are inside event wrappers in the cubase timeline.
Any suggestions why this has happened and how to fix it?

I have the same problem - all of a sudden Cubase 9 is not recognising my projects?

I want to move the Cubase app to an external 2TB drive anyway as the Cdrive is full now - this is a huge problem in itself as after uninstalling Cubase when I tried to download again from Steinberg Site it automatically sent the download to the Cdrive.