In the list of contributed libraries I have a library called SD. This library appears to have nothing in it. When I click on SD, I get no #include files in the sketch. How can I delete it? Is there a file that lists all the libraries and their locations so that I can modify it?
In the directory that stores all you own sketches there is a directory named libraries. Inside the libraries folder there are folders for each of the contributed libraries you have installed over time. Simply delete the folder named SD and it should not longer show up in the IDE's library choices. You have to close then reopen the IDE before it sees the change.
Thanks!