Thanks for that. I don't its an error, i think its the default option.

I have inventor on 3 computers and they are the same on all three.

Now 3D snapping works great and normal, and 2D sketch snapping works within the SAME sketch.

Now when in 3D mode ou can line snap across several sketches, but when in 2D mode you cannot, you can only line snap in the same sketch.

I didn't know if it had anything to do with projecting geometry or a setting.

I have had a look through application settings and cannot find anything immediantly obvious to change this.