I’m not sure if this will cover 100% of the cases, but if you’re on Windows you can use command Findstr that searches for strings in files.
- Open a command prompt.
- Set current directory to the root of your Cubase projects (like “cd C:\MyCubaseProjects”)
- Run command ‘findstr /S /M /I /C:“Omnisphere” *.cpr’ where you change “Omnisphere” to the name of the VST you want to find.
- You will get a list of file names for Cubase files that include the text that you have specified.
Please note that the procedure above doesn’t search for a referenced plugin - it only search for the specified text string. If you e.g. search for “Kontakt” you will get a hit for all files that include the text “Kontakt”, it could be “Kontakt 5”, “Kontakt 6” or any other string that include the text “Kontakt”.
To find real VST references someone needs to write a program that scans your hard drives for Cubase files and manages to decipher the proprietary unpublished file format in search for VST references.