Hi Volvo,
This is what I understood your problem to be:
You have two arrays, Array Old and Array New - make an array containing the elements that exist only in Array New and not Array Old.
If this is the problem you are having, I have included a VI to implement this. It goes through each element in Array New, and searches this element in Array Old. If it does not exist in Array Old, then add the element to a new array (I have called this new array New Entries in the VIs).
I recommend you look at the non-memory efficient implementation, as it is more easier to read. I have also included a memory efficient version of the solution to avoid a build array in a loop, this can be useful if you are dealing with larger array sizes (hundreds of thousan
ds++, depending on your pc memory).
Good luck!