Cant create a slideshow for lock screen in win 10

[jonneymendoza]

Hi i am trying to create a slideshow of images inside my dropbox folder and it wont allow me to from the lock screen's settings menu.

i select a dropbox folder containing all my pics(stored all in C drive btw) and i get an error saying this:

The photo album folder isn't supported because of its location, Please choose another folder

Am not sure why its like this?

any suggestions?