Not the kind of post we look forward to reading unfortunately. However if the "factory" is beginning to see a recurrence it is better to alert us to the situation than to let us stumble in unaware. The Revit Clinic post title today reads: "Data file is corrupt and needs to be manually recovered."
They've created a Knowledge Base article to refer to if you are unlucky enough to encounter this. They've documented procedures for project that use and don't use worksharing. Here's to hoping you never need it.