For the past couple of weeks I've been unable to upload files to my Skydrive using the Mac app. My upload starts OK, but it's very slow, and I have to leave it running overnight or all day. When I get back, Skydrive either says it was unable to upload the file, or it says it's up-to-date, but when I go to Skydrive.com, all my folders are empty.

Uninstalling and reinstalling the app made no difference.