Hi @Scott Bury , can you provide some more context on what you are trying to do ? 

You will need the absolute or relative path of the file from your AIMMS project directory, and the file needs to be on disk. 

One way I fixed this was by syncing the SharePoint file. This way, a copy of the file will be created in a folder in your PC/Laptop. Any changes by other users on the file will be reflected in the synced file as well. A lot like OneDrive/G-Drive/Dropbox/...