The appearance of legends may have changed when the .mxd file was imported to match settings currently available in ArcGIS Pro.
- If you are only concerned with the appearance of the legend and do not need it to update, you can convert it to graphics before importing.
Because the functionality of legends in ArcGIS Pro does not match the functionality available in ArcMap, legends will be converted to use settings available in ArcGIS Pro. The most notable change is the lack of map extent options (Show feature count and Only show classes that are visible in the current map extent) in ArcGIS Pro. These settings are lost until these options become available. There are also fewer formatting and resize options available, so legends not already using the fixed frame fitting strategy in ArcMap will be forced to use the resize behavior Adjust columns and font size. As more functionality is added to ArcGIS Pro, importing legends become less lossy.