The Missing Map Coordinates dialog is displayed when you attempt to render one or more objects with materials whose maps use a map channel other than channel 1. (Channel 1 is an exception because channel 1 mapping coordinates are automatically turned on when you assign a mapped material to an object.) Only maps with Show Map In Viewport toggled on are listed as missing.
To use other map channels, you must assign a UVW Map modifier to the object. In UVW Map, set Map Channel to match the value used in the material.
If the material has multiple maps that use multiple channels, you must assign a separate UVW Map modifier for each channel besides channel 1.
If the object is a NURBS surface sub-object, you don't need to use UVW Map. Instead, set the map channel on the surface sub-object's Material Properties rollout.
The Missing Map Coordinates dialog is also displayed when you open a MAX file that references bitmaps that can’t be found in their original location, or are at a location not specified via the Configure User Paths dialog. To open the MAX file, click the Browse button on the Missing Map Coordinates dialog. This opens the Configure User Paths dialog so you can assign one or more paths for the MAX file to access. These settings are then stored with the MAX file.