I am getting the staging error when attempting to share layers from ArcPro.
"ERROR 999999: Something unexpected caused the tool to fail. Contact Esri Technical Support (http://esriurl.com/support) to Report a Bug, and refer to the error help for potential solutions or workarounds."
Nothing noted in the following link seems to be apparent in my map.
Error: Staging failed (esri.com)
I was trying to test sharing Layer Files (for symbology) produced in ArcMap as a Web Layer in Pro.
The Layer Files were brought into Pro, and tried to share as Web Layer. That is when the error popped up.
However, when I create a blank .mxd in ArcMap and bring in the layer files, I have no issue sharing them as a Service.
Sharing as a Service Definition in Pro results in the same error.
Bringing the feature classes into pro on their own and applying the symbology allows them to be shared as a web layer.
I cannot see why the process would work in ArcMap but not in Pro?