To avoid errors, Sonic Cat recommends copying and pasting the entire license sentence at once into the authorization window rather than typing it manually. Troubleshooting Activation Issues
Ensure the installation folder (usually under Program Files) is not marked as "Read Only," as this can prevent the plugin from saving its registration status.
Open Purity either in standalone mode or within your DAW (like FL Studio or Ableton Live).
If your plugin continues to ask for a serial number every time you open it, try these common fixes:
Once you have installed the plugin, you must authorize it to remove demo limitations. The official user manual outlines these steps:

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