Windows Desktop VB.Net Apps Getting an error 1004 0x800A03EC reading Excel due to 0xC004F057 in Application Event log

We have several Windows Desktop Apps written in VB.2010 and VB.2017 that have been running for a long time at many customers. Then last week Tues, Nov 13, 2018 we started getting customers emails and calls saying the apps are getting an error 1004/0x800A03EC. No app updates where made. Worked one day then stopped.

It doesn't fail here. Tried on 4 different systems. W7/Excel 2013, W10 w/Office 365/Excel 2016.

The failures have happened on W10, 7 and 2012 R2.

Apps are just reading the excel file.

Code Code to initialize ws

ExcelAppObj = New Excel.Application

ExcelAppObj.Visible = pVisible
WB = ExcelAppObj.Workbooks.Open(pFFn, True)
WS = pWB.Worksheets(1)
Ss = "A" & Row & "." & ColNames(UsedColsSht) & Row + 1
Dim War as object = WS.Range(Ss).Value  

In the Application Event log we found this warning Installation of the Proof of Purchase from the ACPI table failed. Error code: 0xC004F057

Just 2 prior was The Software Protection service is starting. Parameters:caller=EXCEL.EXE

which to me indicates that some component in Windows does not think it is genuine. I know that on the system that got the error above both Windows 2012 R2 and Office are genuine.

I am sure this is a MS bug. Can someone point me in the right direction and hopefully a MS fix??????

Thanks and Happy ThanksGiving!

We found the problem but not clear why.

As posted above our code was using a range value of

Ss = "A" & Row & "." & ColNames(UsedColsSht) & Row + 1
s = ws.Range(Ss).value

Note: that a period was used so the range was something like A1.C3 This continues to work in 7 of our 8 systems that we have seen but when we used this format in the excel screen we got a #Field! error. This is a new Excel behavior.

Changing our apps to use a colon instead of a period solved the problem. So the range is now

Ss = "A" & Row & "." & ColNames(UsedColsSht) & Row + 1

or A1:C3

Again it worked in most systems and that cannot be explained. There was nothing in the event logs and the original posting in the header was a false alarm.