Solution to error "The serial number does not belong to a known product"

When attempting to activate a library in Native Access, if you run into an error message about your serial number not belonging to a known product, here are the necessary steps to solve the issue: (replacing "[LIBRARY NAME]" with the name of the affected sample library product (for example, "Evolution Rock Standard"):

1. Quit Native Access

2a. If you are on Windows, delete these files:
C:\Program Files\Common Files\Native Instruments\Service Center\NativeAccess.xml
C:\Program Files\Common Files\Native Instruments\Service Center\[LIBRARY NAME].xml

2b. If you are on a Mac, delete these files:
Macintosh HD > Library > Application Support > Native Instruments > Service Center > NativeAccess.xml
Macintosh HD > Library > Application Support > Native Instruments > Service Center > [LIBRARY NAME].xml
Macintosh HD > Library > Preferences > com.native-instruments.[LIBRARY NAME].plist

3. Restart Native Access and add the serial again.