Not sure whether your question is still relevant. Even if it isn't, maybe someone else will require this information.
I had the same issue, couldn't find a solution on the internet. Apparently nobody else had this issue before.
The solution in my case was within the library path of Python. You can check the library path by running this little Python script:
xdg.BaseDirectory is installed in a subdirectory of
/usr/lib/python2.7/dist-packages but due to the path Python will look in /usr/local/lib/python2.7/dist-packages first. If xdg is in the /usr/local/... subdirectory you will get the same sort of error message. (python2.7 is just an example; could be python3.5 or whatever your version of Python is)
Rename all the xdg stuff in
/usr/local/lib/python2.7/dist-packages to something else (to be on the safe side) and see whether your applications work again. They did in my case.
Please give some feedback whether it worked.