Just a quick note. When working with BIM 360 Design and you are working with others on a project you MUST all be not only on the same Version of Revit, but you also must have the same UPDATES as well.
I had a customer just the other day that was sharing their project with a consultant. They both told me they were using Revit 2018. It turned out one had a straight 2018.3 and the other had 2018.3.1.
The customer with the newer version had no problem with the file, but the other was having issues opening and getting any linked files ( through the desktop connector) to work.
So..... the fix is, to make sure to always check your " Autodesk Desktop App" to see if you have any updates, and talk to your team to make sure you all are on the same "page"!