Why Does KML to Layer Create an Offset?

[rescobar]

Whenever I run kml to layer or kml to geodatabase, if I reproject the layer to state plane, the result is offset. If I create a layer in WGS 84 and then project, I do not see the same offset. Sometimes, the layer is about 4 feet off toward the southwest, but other times, the change is not uniform. Is there any way around this?

[Laura]

Sounds like a WGS84 ↔ NAD83 datum transformation issue. Are you projecting twice - adding a layer to a map with a different projection and then also using the project tool? could cause problems. 

[rescobar]

Do you mean a third projection? Does the projection a map is set do affect how the KML to layer tool runs?

I usually just have the map set to the state plane system I'm using.

[Laura]

What's the source of the KMLS? After running KML to layer, open the properties and confirm what the output coordinate system is. In map properties - is it automatically applying transformations?