Maybe this is just me because I am new, but I pre-washed some fabric last week and it came out of the dryer with edges that were falling apart.

Does this happen to you? What do you do about it?

Do you mean unraveling?
You can use pinking shears or a pinking blade on your rotary cutter.
Some members serge the edges.
Some clip each corner of the fabric to minimize the fraying.
Some wash smaller pieces in lingerie bags

I do a zigzag stitch as close to the edge as I can get. Prevents the tangled mess some! I've thought about picking up some pinking shears as well.

When I prewash I take a pair of scissors with me when I take the fabric out of the washer and cut all the strings off then.

I also zig zag stitch the edges. I tried pinking shears, but still got a mess. So I sew and it comes out fine. A little time spent in prep saves so much in aggravation later.

I just sew a straight line as close as I can to the edge. I still get the occasional strings, but cut them off before I put it in the dryer.

A serger is perfect for this very thing. Just serge across cut edges and no raveling in washer or dryer. If you don't have a serger cutting a small triangle off at the corners helps a lot. If I'm washing small pieces I also use a lingere bag.

Clipping the corner a bit really works! I don't understand why it works, but it does. I forget sometimes though and end up with strings.

I don't normally wash my fabrics, quilt makers are a bit divided on this topic. Here is an article I wrote on the subject that may be useful.
http://www.stitchingcow.com/about/us...uilting-fabric
If you do decide to wash, use a gentle cycle and place in a pillow slip or washing bag. This will also help.
Warmly Lenna

I don't usually wash my fabrics but when I do this works.