Available with Network Analyst license.
The network analysis layer output route will be returned with measures on it. Extra information being returned with the geometry can slow down high-performance client applications.
Solutions
Take any one of the following actions to resolve this issue:
Do nothing. Mark this warning as an exception to avoid seeing it again.
Automatically correct this issue by choosing the appropriate option on the warning's context menu.
Alternatively, you can open the layer properties of the network analysis layer, click the Analysis Settings tab, then change the value for Output Shape Type so that measures are excluded from the output.
More information
The line geometry normally contains x- and y-coordinates for each vertex of a line. When measures are enabled, an extra coordinate or measure is also computed and returned with the geometry. These measures can be on the route outputs of route, closest facility, and vehicle routing problem layers and on the line outputs of service area layers. Turning them off reduces the amount of data to be transferred to the client.