# How can I fix an unintended hole in my mesh?

I've created a hollow object with a Boolean Difference, but it has left a hole in the mesh that I can't seem to fix. There are no vertices on the periphery of the hole itself, and it extends across two faces at right angles to each other.

When I look inside the hollow (as far as I can), I see that there are "shadow" connections between vertices that I would have expected to be unrelated.

I've tried manually reducing the NGON faces to quads and triangles, but it's had no effect on the hole. I've tried Mesh > Cleanup > Fix Holes, also with no effect. I've tried to Beautify the affected faces, again with no effect.

I've attached a link to the file in a state prior to my messing around trying to fix it (approx. 10MB)

Link to the .blend file, approx 10MB

• Using Ctrl+T operator will triangulate Ngon which can be converted to quads after, this can allow skipping deleting face. – Mr Zak Mar 3 '16 at 20:31