I just started having this issue this past several weeks. I had 10.4 downloaded yesterday, and the classic snap appears in some .mxds and not in others. I am in edit mode, which is the only way to initiate and access the classic snapping, but I do not see the tool. What is the issue and how to I get this tool to function. It is an extremely needed tool for my
editing needs
Turning on SnapTips (classic snapping)—Help | ArcGIS for Desktop
About the editing classic snapping environment—Help | ArcGIS for Desktop
Is from the most recent documentation... just search 'classic snap' from the main documentation