Venting is good, but it's hard to help with out more details.

I used the links from my last post to compile a 2 page "Patch Process" for my organization.  It includes all the fixes I felt I could apply, and defines them as Server and Workstation applicable.  It takes me about 15 minutes to apply them to each workstation.  I also keep a spreadsheet of when the fixes are applied to each workstation and a special column for last error dates for both W19tax.exe and PROFXO.P9.  When I get my hands on a workstation I open Lacerte => F10=> Errors and copy the contents to an email which I send myself (Subject [Computer name][User Name] Lacerte Error Log).

I have no real way of telling you what fixes are helping or even working, but do think that setting the AV exceptions to Lacerte folders has made a big difference in at least the PROFXO.P9 errors (which corrupt OUR CUSTOM COLUMN configuration.  I need a couple more weeks to "marinade" the fixes and review the logs.  The other fix which I think maybe helpful is the one which sets security for the Lacerte Application (via the Desktop Icon) and the Lacerte folder.  I have been giving explicit permission to both the user (by name) and Everyone.  Maybe excessive, but I think the security risk, if any, is low to the ile gaurentee of file access.

Related, if you download "Process Monitor" from MS Sysinternals and run this along side Lacerte it may help you identify issues.  (you need to config it to look for "Lacerte" related activity or you will not be able to sift through the results).  This tool clearly identified that our ESET AV was locking files that Lacerte was trying to access. 

Lacerte support is severely limited in what they can do, and so far pretty much what Level 1 has done is tell me to run the WebSetup19.exe with FORCE.  Level 2 was a bit more helpful and furnished me the links above (hence "a Little").  Some of the other fixes, like deleting your Proforma data and redoing I consider to risky.  They do not discuss impact in ANY DOCUMENT.

Like George4Tacks, I will strongly suggest you carve out some time at the next update (maybe push it to Friday noght) and run the WebSetup with Force (option 2) and then go to each workstation and run the client version (option 1).  Monitor the error logs after, but you need to address at least the AV Fix first.