20003: Layer uses a simple marker symbol with a halo
Your layer contains a simple marker symbol with an outline and a halo. The display of this symbol in a basemap layer or optimized map service will potentially differ from your ArcMap display.
- Do nothing. Simply accept the new symbol drawing as is.
- Alternatively, you can modify the size of the marker symbol halo by editing the symbol.
This warning message is simply telling you that the halo size of this symbol will be different in a basemap layer or an optimized map service. This is because the drawing engine used by basemap layers and optimized map services takes the outline size of the symbol into account when calculating the halo, and ArcMap does not.