Blender 2.74 loop tools make circle disappear I have the loop tools addon enabled and when I click the circle button with these verts selected, it just disappears. Why is that?

You can see the selected options in the bottom screenshot. It is worth noting that all the verts are flat on the x plane. Locking in X or not does not change the effect. 

When I use the to sphere operator it squishes the verts on Z and stretches super wide on Y, not making a cirlce.



EDIT:

here is the blend
Your object has a pretty extreme object scale on it. To get an idea of how extreme, this is what it would look like without it:



If you apply the scale to the mesh with &#9096; CtrlA it then works as expected:



See Why are the longer edges being beveled more? for some more detail. Suffice it to say that loop tools sees the mesh without the object scale, and that tall thin hole is confusing it.