Update to 4.7.3 (Win10) Overwriting Data

Hello,

This morning I was prompted to update Basecamp to 4.7.3, which I did.

Upon opening after update, I found that all of my data was gone.  This looks like it was a clean install (which I did not choose - I simply did the in-app update as recommended by the pop-up window). 

I have inspected all associated folders and it appears that the update completely overwrote all files (and I mean ALL of them), as these files now show creation date is today. 

I have done extensive searches on my machine and the "old" data is no longer here.

Fortunately I backup my data so that is not a problem.  However, if I did not have a backup, this would have been a minor "disaster".

Why would the update do this?

I am on a Win 10 Pro machine, version 2004, build 19041.630

Thanks