We definitely have had this problem, really starting in January/February.  Again, Lacerte was unable to help.  We had 50 (fifty) or more client files corrupted this year.  I also whole heartedly agree that it is connected to the new Update process, AND occurs with the first few people accessing the software after the update. 

We have also been utilizing the Lacerte 'module backups' that are prepared daily by Lacerte, for each module, in the software backup file per module to restore files.  However, a few times we had to go back months to find a good file.  Our current workaround, though cumbersome for all on our network, seems to be holding up. 

(1) We only run our updates with "all users" out of the software.  (2) Then as each user updates their workstation, they must then exit the software upon completion, (Lacerte used to end with the software closed), (3) then logout and reboot the workstation.  We figure what errors are being caused during the update might clear when the reboot occurs.  I don't want to jinx it, because it has been a long hard road this year, as you all know, but so far it has stayed quiet the last couple of months.