I upgraded my VST collection, now something is strange/missing. Why?

Try regenerating BWS's VST cache by deleting it. Do this by deleting the following files/folders:

macOS: /Users/your_username/Library/Application Support/Bitwig/Bitwig Studio/index (folder)

/Users/your_username/Library/Caches/Bitwig/vst-metadata (file)

Windows: C:\Users\yourusername/AppData/Local/BitwigStudio/index (folder) C:\Users\yourusername/AppData/Local/BitwigStudio/cache/vst-metadata

Linux: Delete the folder "index" and the file "cache/vst-metadata" in /home/your_username/.BitwigStudio