1) If you get this error, do you also have Explorer/Finder open viewing that file?
Sometimes yes, sometimes no
2) Does any other user have Explorer/Finder open and viewing that file?
no
3) What view mode are you viewing the file in? Specifically, are you looking at the preview image of the VWX file in Explorer/Finder?
If Finder is open we look at the preview image.
4) If you close all Explorer/Finder windows, are you then able to save the file as expected/does autosave resume working as expected?
In our perception, it is random. we cannot find a recurring aspect.