If your Launch X431 CRP919E/ CRP919X BT series scanner appears “This serialNo has not been registered”, please solve it with the following two methods.
Solution 1:
Tap Settings>> About>> Version
Check the APP version, if it is lower than V1.07_2.14, back to Settings interface, and select “Clean up”. After the cache has been cleaned up, tap Upgrade on the main menu to update the software.
Then the problem will be resolved.
Solution 2:
If the problem still exists, try to solve it with the method below which also can solve CRP919 series program exception problem.
Reference:
http://blog.eobdtool.co.uk/how-to-solve-launch-x431-crp919e-program-exception-problem/