good question i am having the same problem I have stitched out a few and they have fallen apart. I only have customizer which came with Janome 350e, and Tajima is the only sofware I have that shows you how it is going to stitch out. stitch by stitch. I would like to know how to tell also.

I think we all did the same thing when we first started out......
I would try & open them to see what you hv, if possible; you might be able to tell how detailed it is. You could always just sew them in white & test them first.

download the free trial but fully working sewwhatpro and let it sew it out for you that way you can see what is going to happen. cost you nothing to find out.
eggyannie in the UK

You could stitch them out on bridal netting or a sheer fabric like organza. They can be used on there own, so it'not a waste of thread. You'll notice if there are unconnected areas, which means it's not FSL.

I have the same problem. I have stitched a few that have fallen apart, but I try to look first to see if it looks like everything is somehow connected.

I do the same as Mops. Hold it up to a light and you will be able to see spaces where there are no connecting stitches.

Thank you, good question, the answers are interesting

That's what I love about my 4D Extra software. You can view the designs with pictures.