I received the message
SkyDrive sync engine stopped working
when SkyDrive tried downloading a file that was currently in use on my system. Ever since then, SkyDrive has been silently crashing* as soon as it tries communicating with the servers. The only time SkyDrive doesn't crash, is when my PC is offline.
SkyDrive itself doesn't seem to think there is anything wrong. Its icon in the File Explorer shows it's syncing, and the SkyDrive app pretends everything has been synced "6 seconds ago". Since I'm running Windows 8.1, there is no app for me to reinstall. What can I do to fix this?
*: When hovering the mouse over the SkyDrive tray icon, the icon will simply disappear.