What is the setting for the ISAVEPERCENT system variable? (This can also be found in the Options dialog, on the Open and Save tab, in the upper left corner (File Save area), as the
Incremental save percentage edit box.)
If it is not set to 0, try doing so and see if your problems of lost changes is resolved. This will force every save to be a full save, and you will lose some of the speed advantages of partial saves, but there were issues a number of years back with AutoCAD Architecture and partial saves, so we have had this set to 0 ever since.
David Koch
AutoCAD Architecture and Revit User
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