I would first try uninstalling and reinstalling PS CC 2014. If that is not enough then uninstall and reinstall LR 5.5.
Another thing to try would be to remove your LR preferences file and let it rebuild—this will reset your preferences to their defaults so you might want to review them before doing this. The location for the preferences file can be found, here:
If that doesn’t work, then try having LR rebuild the SLCache folder, although this is more for licensing issues: