The map content in a mobile map package (.mmpk) using the British National Grid coordinate system is not displayed in ArcGIS Explorer (Windows).

Workaround

1. Open ArcGIS Pro. Right click Map and navigate to Properties > Coordinate Systems. If necessary, set the coordinate system to WGS 1984 Web Mercator (auxiliary sphere).
2. Save the project.
3. Click Share > Mobile Map > Save package to file.
4. Open ArcGIS Explorer Desktop > Click on Import Map > Select the .mmpk file.
5. Double-click the .mmpk file in File Explorer to display the map content.

Steps to Reproduce