I have my design library pathed to L:\, where all my common parts are located. The design library pane shows this at the top of the list as "L:\" next to the books icon.
When I click it, I get the error message "The folder 'L:\' does not exist. Do you want to remove it as a Design Library file location reference?".
I say no, and then SW opens the library and I am able to add parts normally. But this popup is annoying, especially when I accidentally click yes, and then have to re-path my library.