Seams coming apart when I start hand quilting
 

I'm making my LAST quilt unless someone can tell me why my seams in the blocks look like they are coming apart when I hand quilt. I'm doing the same as I've always done when making the quilt top. Help, please?

Are the seams actually coming undone? Or is the fabric fraying at the seams? You can see the stitches when the seam fabric is pulled? Either bad fabric or machine stitches have really loose tension problems/stitch length too long. A picture would help get better answers for you.

Are you talking about hand pieced seams coming apart?

we need a little more information or pictures before we can really help here- where are the seams coming apart? did you press them to one side or open? are the fabrics loosely woven and fraying? is it around the outer edges of a block? where a stay stitch would help? were the blocks hand or machine pieced? if hand pieced- did you knot the ends of your threads and do a few back stitches ever few stitches? if machine pieced did you secure any seam not crossed by another line of stitches?
so many things----give a few details we may be able to help

Could be lots of things. Rotten thread, too narrow seam allowance, tension too too loose on machine, loose weave fabric fraying. If it is at the edge of the quilt with no border, it could just be the stress of pulling on it without any backstitching.
Is it throughout the whole quilt? Let's see pictures.