I think I saw this question posted before but I couldn't find it so I am sorry if this is a repeat.
I have made MMF a couple of times and each time when I am kneading the confectioners sugar, I am finding clumps of sugar in the MMF. Do I have to sift the sugar before I add it or is there another way to avoid the lumps. I have tried to avoid handling the MMF too much because I thought it would get 'tough' if rolled and kneaded too many times. Any tips would be appreciated.
thanks.

Some people find sifting to help. I have never had the lumps and I never sift.
But if you are gettin' the lumps, try sifting next time. I know other people do it.

Don't be afraid to work your MMF. It's not like bread dough, it actually gets better the more you work it.

If your MMF is lumpy then sifting can help, but most likely you just need to do more kneeding.

I also get small lumps of powdered sugar in my MMF. I am new to this fondant experience, but I found that when I add my color and knead away, the warm of my hands melts the lumps away! I noticed the MMF is much for friendly to work with once it gets all warm and pliable. I was up until 4am last night playing with it!

I refuse to sift... I bought a sifter and after 10 minutes of sifting and having only 1/4 cup go through the darned thing, I gave up! Talk about hand cramps!

If you buy the 10X confectioners sugar, you won't have to sift it. I also hate to sift, but I found that if I put the sugar in a metal mesh colandar (just realized I don't know how to spell that word) and shake it into a bowl, you won't kill your hands and it works really well.

I also have never sifted and have no problems. I don't know what kind of powdered sugar you are using. I use C&H and it works great. Also warm the fondant up a bit in the microwave (around 20+ seconds, depending on how much you are working with) and then knead the heck of it. The more you knead, the easier it is to work with.

I also use the metal collander - I haven't had any clumps with my MMF. Also, knead knead knead until you get the smooth texture that you are looking for. It sometimes takes awhile to get the exact feel that you are looking for.

I think it has a lot to do with the humidity in your area. I was having trouble with clumps in my MMF, but I started sifting it through a metal mesh collinder and that took care of the problem.