If your KONTAKT PLAYER Instrument unexpectedly switches to DEMO Mode, you may have unintentionally activated a feature that is only available in the full version of KONTAKT. 
This usually happens if:
- You load a sample from the Files Tab in KONTAKT PLAYER's Browser (.wav, .aif, .rex, .rx2, etc. files). To load your own samples into KONTAKT you must have the full version rather than the free KONTAKT PLAYER.
- You load any KONTAKT Instrument (.nki/.nkm/.nkb files) from the Files Tab in KONTAKT PLAYER's Browser which requires the full version of KONTAKT to work. Please refer to the KONTAKT Instrument's manufacturer's website to know if the full version of KONTAKT is required to use the Instrument.
Note: please check this comparison chart for more details on the available features of the free player compared to the full version of KONTAKT.