I'm able to select the Core Library or EXP Libraries from Stylus RMX but if I select the User Libraries or User Favorites, it 'stays' with my previous selection (which is the Core or EXP Libraries).

Apparently I have no way to select the User Libraries despite the fact that this folder is not empty, I copied one or two libraries there.

Any insight are more than welcome, thank you.

 

Sound like the libraries are not set up correctly.
Check the core library and make your user library the same format - not too many sub folders.

If your core library is:
Folder
Subfolder
Data

and your user library is:
Folder
Subfolder
Subfolder
Data

then that's your problem.

 

Is your sage folder structure correct, should look like this

 

MaschineMan and BoogieWoogie: A big thanks to both of you, problem solved!