It’s not actually using 3 forward slashes. It’s broken down like this:
file://
/Users/…..
On a mac, ‘/’ denotes the root drive (just like all unix/linux os’). I tried it on my Windows computer and I don’t get a syntax error, rather I get a file not found error. Here is the path that I used:
C:\User\andrew.riebe\Desktop\source.txt
This is a really annoying thing that should simply work (as I can see it working properly in all the tutorials).
Thanks for the help.