After successfully upgrade to Windows 8.1 from a native Windows 8 (which Skydrive app worked just fine) some files cannot be sync. All files are on the same folder but some of them (.wmv and .ppt extensions) keep trying to sync since two days ago. There are in this folder other files of same extension but they sync, even if a new folder is created and the file moved into it. There is any troubleshooting that can be applied on this case?