This is a Quick Fixed that worked for me and for those receiving a Unity Time Sync Error!
Most sites are going to tell you to delete your Unity Library and Re-Import All Assets. While this may end up being the fixed, First Try This:
Look at the file Error in Unity Console window, If all the folders it references leads back to one folder then you can do this.
1. Open Computer, Navigate your C:// drive to find that folder.
2. Drag that folder to your Desktop. ( Keep that window you found it in "Open" )
3. After it compiles, Re-Drag it back to it's Folder Window.
Unity will re-import the file structure and Time Sync is Fixed.