Version 2.2.0 - crashes

Have been using Audacity for over a year. But now it continually crashes. Keep have to Control Save and re-open the programme after very few changes to the tracks.
Now it crashes and when you open the file - all of the wave forms (and sounds, edits, etc) have been removed. The tracks with the names are still there but nothing is left of the previous work.
Have spent 8 hours creating a radio play to upload to and now ALL of the data (and effort) has gone.
It crashes when you copy and paste, when you move tracks around.
Have been working on a Windows 10 Surface Book so switched to iMac to see if that would work.
Exactly the same issues.

Not a happy camper - what am I doing wrong?

Any help/suggestions would be appreciated.

Does this have anything to do with “Chains”?