In AutoCAD, as a general rule, layer 0 must always be on, thawed, and unlocked (and it helps if you never ever draw anything on it ever). Looks like that's all it was.
FWIW your posted PDF file has this information in it, so I went by that reality
In AutoCAD, as a general rule, layer 0 must always be on, thawed, and unlocked (and it helps if you never ever draw anything on it ever). Looks like that's all it was.
FWIW your posted PDF file has this information in it, so I went by that reality