Did you do the whole standard procedure of:
Deleting clientregistry.blob,
Verifying game cache,
Disabling or uninstalling addons,
Restarting Steam/computer?
EDIT CUZ MOBILE LACKS COMMENTS: clientregistry.blob is in the main Steam folder, delete that. If it doesn't work, then I'm not sure I can help. I solved my main problems by upgrading to Windows 10 :U