When you install Revit on a computer, some important files reside in the UserDataCache folder, which is located here:
C:\ProgramData\Autodesk\<product and release>\UserDataCache
That folder contains the following important files, which provide default settings for each user:
When you start the Revit software for the first time, your roaming user profile folder is created in the following location:
C:\Users\<username>\AppData\Roaming\Autodesk\Revit\<product and release>
The files in UserDataCache are copied to your user profile folder. As you use Revit, the software refers to the information stored in your user profile files, not to the files in UserDataCache.
What does this mean?