Have a batch of MMF. I used it 2 nights ago and it was dry, I added crisco and it smoothed out nice. Now it's crumbly. I tried adding crisco, still crumbly. I microwaved it and also tried water. Why is it crumbly? Do I give up and make a new batch?

Is it colored or white???
Try putting it in the microwave for 5-10 seconds and knead it again. Sometimes I have to add up to 1/4 c of shortening to mine.

It's colored. The microwave didn't really help and the shortening just made it greasy and crumbly. AAAHHHH!

Sometimes, for whatever reason, if there is tons of color in it, especially dark colors, it can get crumble. My only suggestion is tons of crisco and microwave it...I ended up throwing some burgundy stuff away after making accents with it. It was gonna be covering a cake but there was no way I was ever gonna roll this stuff out....!!!

Dry and crumbly (that is not fixed by crisco) usually means you need to knead some water into it to soften it. You may need to microwave it a bit to soften it enough to work the water in.

I had this same problem, I ended up buying some premade fondant just to see what I can do with it. Someone here suggested adding glycerine to it to give it some elasticity. I have yet to try it but I just bought some tonight. Also, it might just have to much sugar in it. Try adding some more marshmellow.

I tried water with mine and it made it terribly sticky...I found the crisco to make it hold together and be pliable enough to make the accents.

Ok I know why mine was crumbly, I made a med gray and it must have been the color. Crisco doesn't seem to help much. But, I forgot to mention that I was using Wilton Fondany only because I used a coupon and I was using it for decoration, not to eat.

I had this problem when I made navy blue MMF. Nothing would work and I was going crazy until I decided to mix it with Wilton fondant. I did a 50/50 mixture. I also added Lorann oil while flavoring to mask Wilton's taste. Well, it turned out pretty good! I got the flavor of MMF and the Loran oil and the texture of Wilton. HTH

I had crumbly MMF once and was so frustrated, only to realize later that I had used a 10 oz package of marshallows on accident!