It’s easiest just to walk through this problem rather than to ‘describe’ it.
Occasionally the following odd problem will happen…
Open a CPR created in an earlier version of Cubase. Said CPR had a plug-in no longer on offer in C9.
Delete that channel/track.
Backup CPR to new folder and name.
Re-open new CPR and get an error: ‘The following plug-in is not supported…’ and it refers to the track I deleted in step #2.
Click through and CPR works fine.
Is there -any- way to get rid of that ‘phantom plug-in’ warning?