Revit cannot run the external application "NaviateAC"
When you start Revit after installing a Naviate product you are getting this error message.
This message says that there is an issue within your "userconfig" file on your machine.
Please rename that file mentioned in the error message and start Revit again. Everything should work as normal.
There will be a different path to the User Config file, depending on what version you are running and the date you get this error. The filepath below is an example from my computer and is related to a User Config file for Revit 2021 that happened on 9 september 2021.
You can use this link to see all your config folders for the different Autodesk Revit versions.