Tool path Loading

I have attempted to load an STL file to carve and every time I aske to generate the tool path is spins and says there was an error. I have to reload Easel or start form the beginning. When I change the finish bit from a ball nose to a straight 1/8" double flute it will produce the tool path and carve. The quality from an 1/8" end mill will not cut it. Any input on what I can do to get it to load any size ball nose I choose without fighting an uphill battle would be greatly appreciated. Thank You

by selecting a smaller bit you may have reached the limitations of Easel itself and or the processing capabilities of your own PC as the toolpaths are calculated on the users PC remotely.