If you're experiencing issues with Waves plugins failing to load, receiving errors when scanning your Waves plugins, or Waves plugins prompting you to select your Waves installation folder please try the following:
Before proceeding verify that you're running FL Studio 12.1.3 or higher, to check your FL Studio version navigate to "? > About" in the Toolbar. If not, download the latest version HERE.
Perform a verified plugin scan
If problems persists try the following Waves installation instructions:
Once the process is complete, restart your computer and launch FL Studio then follow the verified plugin scan instructions above.