4926? That is an awful lot of plots. Do you really need that many? Why not have just how many plots you need for each color, and put each data point into a plot that is assigned that color.
Do you know if you actually have that many plots?
Where is this data coming from?
in your block diagram image, you have a blue wire going to the add function going to the N of the loop. You have another blue wire that is laying right over top (or right under) going to a tunnel and going into the loop. Clean up your wiring diagram so they don't overlap. Put probes on those wires and see if they make sense.
Wire are you adding an integer to the array size and putting into N? The loop is auto-indexing off the array of that cluster. Assuming that blue wire is a positive number, the For Loop is only going to run a number of times equal to the size of that cluster array.
I don't know if there is a limit to the number of plots in LabVIEW. It certainly seems like there would be, but I don't know what that number would be.
EDIT: Well I created a test VI that created an XY graph with a huge number of plots. I was able to create one with 100,000 plots and set the point style without a problem.
That makes me think the problem is either with the numbers you have in those integers like I pointed out above. Or the other possibility is that you hadn't written all the data to the graph yet and are trying to set a point style. A plot doesn't exist in a graph until it has received data. You might have a dataflow problem.
