Solid Tools Subtract not working

I have to solids - I am making a “key” for two model pieces to fit together once printed. When I use Union to adhere th male key to the body, everything works as it should. However when I fly the key around and try to subtract it from my model and make the female half of the key, the key just vanishes. I can use any other solid tool and it works as expected. I have used subtract in this same model and it has also worked. Why not this one piece?

It’s suppose to vanish when you use Subtract. Use Trim instead of you don’t want to lose the object.

Share the .skp file.

It’s not supposed to vanish and leave nothing behind. It’s supposed to subject its own shape from the second shape. See in picture three how it’s simply gone and there is a flat surface left behind?

I’ve been using SketchUp since long before the Solid Tools were introduced. I know how they are supposed to work. The first object selected is subtracted from the second and is deleted in the process.
Subtract

If you aren’t getting a similar result, there’s something amiss with your workflow. As I wrote, share your SketchUp model.

By the way, your profile says you are using SketchUp Free (web). That version doesn’t include the Solid Tools. What version are you actually using?

If it is not removing anything from the second solid there is likely a problem with something… how big is your model? Is it possible the hole would have faces with edges smaller than .001”?

If you don’t share your model as Dave requested it’s gonna be difficult to help you solve this issue.