Hi Chris, sorry to hear about this, I know its a real pain when you've spent hours on something and it doesn't save or corrupts somehow. I haven't heard of that being a particular issue with 2018.2, but I'll be on the lookout for it. Can you please post back to let us know the outcome with the Support ticket?
[Program Manager - Tableau Community]
Thanks for the response. I couldn't reliably recreate the issue in a short space of time, and didn't want to risk losing what I'd worked on a third time, so decided to roll back to 2018.1 for a bit. Unfortunately this wasn't much of a help with diagnosis, so I'm going to set up a regular backup, go back to 2018.2 and see if there are any issues that way.
If anyone else has a similar issues I'd be interested to know.