I developed a number of webapps with Web AppBuilder v2.22. Given that WAB thru ArcGIS Online is now at v2.3, I installed the WAB Developer v.2.23 API. However when I try to upgrade a webapp (#2) to v2.23 as follows:
node_x64 upgrade < c:\arcgis\arcgis-web-appbuilder-2.22 > 2
I get "Access is denied". I even tried running CMD.EXE with Admin privileges and I get the same thing. The above happens with all my webapps, even the most basic, non-customized ones.