Any idea what is this "face". I tried modeling->delete face but error came:
"Delete failed...remaining faces cannot close the area left after deleting...Neighbor is self-intersecting"
Have also tried: Optimize face(Sheet metal)
Turn off the check in the box 'heal' in the settings of the Delete Face command
Have you tried to "unsew" the surface and use "delete body' to delete this face?
The heal option that was mentioned earlier works also.