One way sync from a folder to UR

[science2002]

Thanks @kinnok. I thought myself of your first solution (relative paths).
The fact in my case is that I usually have a folder structure like this

C:\UR\New ebooks\ (1)
C:\UR\Old ebooks 2019\ (2)
etc.

Then as time goes by the folder "New ebooks" becomes (2), i.e. "Old ebooks YYYY", etc.
I would like to have UR that keeps track of both (1) and (2), so its database is placed in folder UR. In this way, it exploits relative paths (no need to know the letter of the HDD), but I would still need to change the URL folder name from (1) to (2) when time comes.

I will look into your second method then. Thanks again.