Mesh disappears when removing parent armature relation I have a mesh parented to an armature that I want to remove and re-rig with a new armature 



New armature: kaini_rig in the scene tree top right. I'm basically just remaking the UE4 skeleton.

However, whenever I try what he does at 20:45 in this video - removing the parent armature from the mesh in the Relations section of the Object tab - the mesh totally disappears (this happens in 2.80 as well) 



All I did in the above is press the X on the Parent field, where my mouse is. The eyeball icon is still active on the mesh, so I'm not sure why it is not showing. The same thing happens when I try to change the parent relation to my armature vs simply removing it.
Did you notice the mesh dimensions in the 3D view sidebar? It goes from meters and centimeters to centimeters and millimeters. It's not disappearing, but shrinking to such tiny dimensions you can't see it with the armature visible.

Instead of removing the parent at the Object panel, try the following: With the mesh selected and cursor on the 3D view, press Space, then Clear Parent > Clear and Keep Transformation.

That should preserve the transformations affecting the mesh while it was parented to the armature, what won't happen if you simply remove the parent from the panel.