When you open a map or scene, the data referenced by each of the layers in the map is accessed. When the data source has been moved, renamed, deleted, or is otherwise
inaccessible, that layer doesn't draw, and its broken status is indicated in the Contents pane with a red exclamation point 
icon.
If the referenced data source is inaccessible, you can repair the data source link. Alternatively, you can leave the broken layer as is and continue to work with the map if you are not able to repair the link immediately, or you can remove the layer if it is no longer necessary. If the connection to the data source of a web layer is broken, you cannot repair the data source. Instead, remove the web layer and add the new web layer with an updated data source to the map.
You can repair data source links with arcpy.mp. For more information about automating this with Python, see Updating and fixing data sources.
Repair a broken data source link for a layer
To repair a broken data source connection for a layer, follow these steps:
- In the Contents pane of the map, right-click a layer, and click Properties to open the Layer Properties dialog box.
- On the Source tab, click Change data source
and browse to the data source. - Click OK.
Repair broken data source links for multiple layers
You may find that several layers in
your map need repairing. For example, if a geodatabase containing
data sources that are used for multiple layers in your map has been
moved or renamed, all these layers must be repaired. You can filter the view of the Contents pane to show only those layers with broken data source links. In the Contents pane, click the Filter button 
and click Broken data link.
When the repair to the data link is made from the Contents pane, the data source is repaired for the selected layer along with any other broken layers in the map, if it can find their data sources in the same location.
To repair broken data source links for multiple layers, follow these steps:
- In the Contents pane of the map, click the red exclamation
point button next to the layer to open the
Change Data Source dialog box.
- Browse to the source, select it, and click OK.
Tip:
You can also update all the data sources in a project at once. See Update data sources for more information.