The most common causes of layer creation in a new drawing is:
1. It is in the template
2. The user made it
3. It is in a the acad.lsp s::startup function
4. It is created by an add-on
5. It is created by a block or xref
6. It is created by an automatically run routine
7. The user forgot he made it .... again ....
To troubleshoot follow these guidelines:
1. Open AutoCAD and create a new drawing without a template.
The layer exists - Go to 2
The layer does not exist - Problem is in template
2. Set SDI to 0 and ACADLSPASDOC to 0, then create a NEW drawing (without closing AutoCAD) without using a template.
The layer exists - Go to 3
The layer does not exist - The problem is in the ACAD.LSP file
3. Check the contents of the Startup Suite and remove all autoloading routines. Then create a new drawing without a template.
The layer exists - Go to 4
The layer does not exist - The problem is in a program loaded by the Startup Suite
4. Using the VBA Manager, unload all VBA projects, then create a new blank drawing.
The layer exists - Go to 5
The layer does not exist - The problem is in a VBA program
5. Leaving all settings the same, close AutoCAD and restart AutoCAD from the executable, not a shortcut.
The layer exists - Go to 6
The layer does not exist - The problem is in an autoloading Add-on referenced by the profile *.arg
6. Tie a rope to the computer and use it for an anchor on your next fishing trip.
The computer no longer exists ...