There are 3 file types use the .MNU file extension:
1. AutoCAD Interface Layout File
Interface layout definition file used by AutoCAD 2D and 3D CAD software as well as 3ds Max 3D modeling software; contains ASCII text definitions that specify the display properties of user interface elements; used for customizing the layout of the user workspace.
MNU files were used by older AutoCAD versions prior to AutoCAD 2006. The default interface layout was stored in a file named acad.mnu, which could be supplemented with additional custom layouts.
For AutoCAD software, MNU files are similar to .MNS files, which use the same format, but do not contain any comments or special formatting.
NOTE: MNU files were replaced by .CUI files in AutoCAD 2006. CUI files were then replaced by the new .CUIX files in AutoCAD 2010. CUIX files can be generated from MNU files in AutoCAD 2010 using the Transfer tab of the CUI command.
Updated: July 23, 2010