Revit 2017 - Work disappearing after Synchronizing/Closing/Reopening?

[nharburger]

I am working in 2017 and i came across something I KNOW i had done the previous week - but seems to be back to how it was prior to my edits. I first assumed a project team member undid my work, but when i went to inquire, i learned that this is an issue that has been plaguing the project team for months now. They have just been quietly dealing with it (redoing missing/reverted work as they find it)- but has anyone else had similar experiences? is this a 2017 bug? or is the project file just seriously corrupted?

[DaveP]

I'd bet that someone made another copy of the Central file in another folder somewhere and never made a new Central out of it.
So they think they've got their own Project, but they are actually making edits to your Central.
Go into the Collaborate Tab and Show History to see who has saved when.
If you catch it soon enough, you can also use the WorkShareMonitor. There's a little icon in the upper right to Show History. It gives you a little bit more detail, but only 3 days worth.