Object has edges but no (visible) faces

Used to be a normal “solid” group. Gets hidden while working on other things. Now it only has edges. Entity Info says it has six faces, but they are not visible. It’s as though I am in Wireframe mode.

Is the object hidden with Hidden Geometry turned on? Or are you using Layers incorrectly with the faces on a layer other than Layer 0? If not, share the file.

Got them back with Unhide All Entities, although no other method showed them as hidden.

Showing hidden geometry will not show things that are hidden and with a layer tag that has visibility turned off. To see all hidden objects, make sure all layers are visible. Sounds like your wall got onto a different layer, and hidden as DaveR suggested, better check for raw geometry off layer 0.

I did run Geometry to Layer0. The edges were on Layer0, couldn’t select a face to check. Outliner showed it as not hidden - could toggle Hidden on and off. Toggled the layer the object is on on and off. Moved it to a different layer. Tried Edit Unhide All. Show Hidden Geometry showed it was hidden. Select Only Hidden didn’t work.

Somehow just the faces got hidden. Maybe Layers Panel went wonky.

I’m going to go out on a limb here and suggest that it’s a layers issue caused by your habit of changing the active layer and exploding groups.
The model you attached some time back with the tiles was a perfect example of that sort of poor workflow.
When a group is exploded the raw geometry inherits the group layer. So it is possible to mix raw geometry on different layers. Changing the active layer also exacerbates the problem.
So always leave Layer 0 as the active layer, Edit groups rather than explode them and if for some reason you do explode something set the raw geometry from the exploded group to layer 0.
Use Hide sparingly as it is contextually sensitive and easy to lose what you have hidden.